Optical sheet assembly and liquid crystal display apparatus having the same

ABSTRACT

A liquid crystal display panel includes a liquid crystal layer having a twist angle of ±10 degree. An upper polarizer is disposed over an upper substrate of the liquid crystal display panel, and includes an absorption axis forming at an angle of 47±10 degree in a clockwise direction with respect to a major axis. An upper λ/2 retardation film is disposed between the upper substrate and the upper polarizer, and includes Δnd 1  of 260±10 nm and a slow axis forming at an angle of 166±10 degree in the clockwise direction with respect to the absorption axis. An upper λ/4 retardation film is disposed between the upper substrate and the upper λ/2 retardation film, and includes Δnd 2  of 140±10 nm and a slow axis forming at an angle of 111±10 degree in the clockwise direction with respect to the absorption axis. Therefore, the optical condition of the optical film assembly is optimized to improve an image display quality.

CROSS-REFERENCE OF RELATED APPLICATIONS

The present application claims priority from Korean Patent ApplicationNo. 2003-53264, filed on Jul. 31, 2003 and Korean Patent Application No.2003-53266, filed on Jul. 31, 2003, the disclosure of which is herebyincorporated herein by reference in their entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an optical sheet assembly and a liquidcrystal display apparatus having the optical sheet assembly. Moreparticularly, the present invention relates to an optical sheet assemblycapable of optimizing optical condition and a liquid crystal display(LCD) apparatus having the optical sheet assembly.

2. Description of the Related Art

A reflective type LCD apparatus, in general, displays an image using anatural light that is provided from an exterior to the reflective typeLCD apparatus so that an amount of the natural light decreases in a darkplace, thereby deteriorating an image display quality.

A transmissive type LCD apparatus displays the image using an artificiallight that is generated from a light source, for example, such as abacklight to display the image having a good quality in the dark place.A power consumption of the transmissive type LCD apparatus, however, isgreater than that of the reflective type LCD apparatus. Therefore, asize of a portable display apparatus having a battery may be increased.

A transmissive-reflective type LCD apparatus includes a reflection modeand a transmission mode to display the image having good quality usingthe artificial light in the dark place. The transmissive-reflective typeLCD apparatus also displays the image using the natural light in abright place so that a power consumption of the transmissive-reflectivetype LCD apparatus is decreased.

The optical condition of the transmissive-reflective type LCD apparatusis determined by the reflection mode so that the transmission mode ofthe optical condition is designed with respect to a black color.Therefore, a light transmittance of the transmission mode of thetransmissive-reflective type LCD apparatus is decreased so that thelight transmittance of the transmission mode of thetransmissive-reflective type LCD apparatus may be a half of that of thetransmissive type LCD apparatus.

BRIEF SUMMARY OF THE INVENTION

The present invention provides an optical film assembly capable ofoptimizing an optical condition to improve a light transmittance, acontrast ratio and a viewing angle.

The present invention also provides a liquid crystal display (LCD)apparatus having the optical film assembly.

The optical film assembly for a liquid crystal display panel inaccordance with an aspect of the present invention includes an upperpolarizer, an upper λ/2 retardation film and an upper λ/4 retardationfilm. The liquid crystal display panel includes a liquid crystal layerhaving a twist angle of about −10 degree to about +10 degree. The upperpolarizer is disposed over an upper substrate of the liquid crystaldisplay panel. The upper polarizer includes an absorption axis formingabout 37 degree to about 57 degree in a clockwise direction with respectto a major axis of a liquid crystal of the liquid crystal layer, and theliquid crystal is disposed adjacent to the upper substrate. The upperλ/2 retardation film is disposed between the upper substrate and theupper polarizer. The upper λ/2 retardation film includes a first opticalcharacteristics Δnd1 of about 250 nm to about 270 nm. A slow axis of theupper λ/2 retardation film forms at an angle of about 156 degree toabout 176 degree in the clockwise direction with respect to theabsorption axis. The upper λ/4 retardation film is disposed between theupper substrate and the upper λ/2 retardation film. The upper λ/4retardation film includes a second optical characteristics Δnd2 of about130 nm to about 150 nm. A slow axis of the upper λ/4 retardation filmforms at an angle of about 101 degree to about 121 degree in theclockwise direction with respect to the absorption axis. Here, ‘Δn’,‘d1’ and ‘d2’ denote an anisotropy of a refractive index, a thickness ofthe upper λ/2 retardation film and a thickness of the upper λ/4retardation film, respectively.

The optical film assembly for a liquid crystal display panel inaccordance with another aspect of the present invention includes a lowerpolarizer, a lower λ/2 retardation film and a lower λ/4 retardationfilm. The liquid crystal display panel includes a liquid crystal layerhaving a twist angle of about −10 degree to about +10 degree. The lowerpolarizer is disposed under a lower substrate of the liquid crystaldisplay panel. The lower polarizer includes an absorption axis formingat an angle of about 38 degree to about 58 degree in a clockwisedirection with respect to a major axis of a liquid crystal of the liquidcrystal layer, and the liquid crystal is disposed adjacent to the lowersubstrate. The lower λ/2 retardation film is disposed between the lowersubstrate and the lower polarizer. The lower λ/2 retardation filmincludes a first optical characteristics Δnd1 of about 260 nm to about280 nm. The slow axis of the lower λ/2 retardation film forms at anangle of about 65 degree to about 85 degree in the clockwise directionwith respect to the absorption axis. The lower λ/4 retardation film isdisposed between the lower substrate and the lower λ/2 retardation film.The lower λ/4 retardation film includes a second optical characteristicsΔnd2 of about 120 nm to about 140 nm. A slow axis of the lower λ/4retardation film forms at an angle of about −1 degree to about 19 degreein the clockwise direction with respect to the absorption axis. Here,‘Δn’, ‘d1’ and ‘d2’ denote an anisotropy of a refractive index, athickness of the lower λ/2 retardation film and a thickness of the lowerλ/4 retardation film, respectively.

The optical film assembly for a liquid crystal display panel inaccordance with still another aspect of the present invention includes alower polarizer, a lower λ/2 retardation film and a lower λ/4retardation film. The liquid crystal display panel includes a liquidcrystal layer having a twist angle of about −10 degree to about +10degree. The lower polarizer is disposed under a lower substrate of theliquid crystal display panel. The lower polarizer includes an absorptionaxis forming at an angle of about 122 degree to about 142 degree in aclockwise direction with respect to a major axis of a liquid crystal ofthe liquid crystal layer, and the liquid crystal is disposed adjacent tothe lower substrate. The lower λ/2 retardation film is disposed betweenthe lower substrate and the lower polarizer. The lower λ/2 retardationfilm includes a first optical characteristics Δnd1 of about 260 nm toabout 280 nm. A slow axis of the lower λ/2 retardation film forms at anangle of about 95 degree to about 115 degree in the clockwise directionwith respect to the absorption axis. The lower λ/4 retardation film isdisposed between the lower substrate and the lower λ/2 retardation film.The lower λ/4 retardation film includes a second optical characteristicsΔnd2 of about 120 nm to about 140 nm. A slow axis of the lower λ/4retardation film forms at an angle of about 161 degree to about 181degree in the clockwise direction with respect to the absorption axis.Here, ‘Δn’, ‘d1’ and ‘d2’ denote an anisotropy of a refractive index, athickness of the lower λ/2 retardation film and a thickness of the lowerλ/4 retardation film, respectively.

The optical film assembly for a liquid crystal display panel inaccordance with still another aspect of the present invention includesan upper polarizer, an upper λ/2 retardation film and an upper λ/4retardation film. The liquid crystal display panel includes a liquidcrystal layer having a viewing angle of about 170 degree to about 250degree in a clock direction with respect to a horizontal direction ofthe liquid crystal display panel and a twist angle of about −10 degreeto about +10 degree. The upper polarizer is disposed over an uppersubstrate of the liquid crystal display panel, the upper polarizerincluding an absorption axis forming at an angle of about 67 degree toabout 87 degree in the clockwise direction with respect to thehorizontal direction of the liquid crystal display panel. The upper λ/2retardation film is disposed between the upper substrate and the upperpolarizer. The upper λ/2 retardation film includes a first opticalcharacteristics Δnd1 of about 250 nm to about 270 nm. A slow axis of theupper λ/2 retardation film forms at an angle of about 81 degree to about101 degree in the clockwise direction with respect to the horizontaldirection. The upper λ/4 retardation film is disposed between the uppersubstrate and the upper λ/2 retardation film. The upper λ/4 retardationfilm includes a second optical characteristics Δnd2 of about 130 nm toabout 150 nm. A slow axis of the upper λ/4 retardation film forms at anangle of about 136 degree to about 156 degree in the clockwise directionwith respect to the horizontal direction. Here, ‘Δn’, ‘d1’ and ‘d2’denote an anisotropy of a refractive index, a thickness of the upper λ/2retardation film and a thickness of the upper λ/4 retardation film,respectively.

The optical film assembly for a liquid crystal display panel inaccordance with still another aspect of the present invention includes alower polarizer, a lower λ/2 retardation film and a lower λ/4retardation film. The liquid crystal display panel includes a liquidcrystal layer having a viewing angle of about 170 degree to about 250degree in a clock direction with respect to a horizontal direction ofthe liquid crystal display panel and a twist angle of about −10 degreeto about +10 degree. The lower polarizer is disposed under a lowersubstrate of the liquid crystal display panel. The lower polarizerincludes an absorption axis forming at an angle of about 8 degree toabout 28 degree in a clockwise direction with respect to the horizontaldirection of the liquid crystal display panel. The lower λ/2 retardationfilm is disposed between the lower substrate and the lower polarizer.The lower λ/2 retardation film includes a first optical characteristicsΔnd1 of about 260 nm to about 280 nm. A slow axis of the lower λ/2retardation film forms at an angle of about 113 degree to about 133degree in the clockwise direction with respect to the horizontaldirection. The lower λ/4 retardation film is disposed between the lowersubstrate and the lower λ/2 retardation film. The lower λ/4 retardationfilm includes a second optical characteristics Δnd2 of about 120 nm toabout 140 nm. A slow axis of the lower λ/4 retardation film forms at anangle of about −1 degree to about 19 degree in the clockwise directionwith respect to the horizontal direction. Here, ‘Δn’, ‘d1’ and ‘d2’denote an anisotropy of a refractive index, a thickness of the lower λ/2retardation film and a thickness of the lower λ/4 retardation film,respectively.

The optical film assembly for a liquid crystal display panel inaccordance with still another aspect of the present invention includes alower polarizer, a lower λ/2 retardation film and a lower λ/4retardation film. The liquid crystal display panel includes a liquidcrystal layer having a viewing angle of about 170 degree to about 250degree in a clock direction with respect to a horizontal direction ofthe liquid crystal display panel and a twist angle of about −10 degreeto about +10 degree. The lower polarizer is disposed under a lowersubstrate of the liquid crystal display panel. The lower polarizerincludes an absorption axis forming at an angle of about 152 degree toabout 172 degree in a clockwise direction with respect to the horizontaldirection of the liquid crystal display panel. The lower λ/2 retardationfilm is disposed between the lower substrate and the lower polarizer.The lower λ/2 retardation film includes a first optical characteristicsΔnd1 of about 260 nm to about 280 nm. A slow axis of the lower λ/2retardation film forms at an angle of about 47 degree to about 67 degreein the clockwise direction with respect to the horizontal direction. Thelower λ/4 retardation film is disposed between the lower substrate andthe lower λ/2 retardation film. The lower λ/4 retardation film includesa second optical characteristics Δnd2 of about 120 nm to about 140 nm, aslow axis of the lower λ/4 retardation film forming at an angle of about161 degree to about 181 degree in the clockwise direction with respectto the horizontal direction. Here, ‘Δn’, ‘d1’ and ‘d2’ denote ananisotropy of a refractive index, a thickness of the lower λ/2retardation film and a thickness of the lower λ/4 retardation film,respectively.

The liquid crystal display apparatus in accordance with an aspect of thepresent invention includes a liquid crystal display panel, an upperpolarizer, an upper λ/2 retardation film and an upper λ/4 retardationfilm. The liquid crystal display panel includes an upper substrate, alower substrate corresponding to the upper substrate and a liquidcrystal layer disposed between the upper and lower substrates to have atwist angle of about −10 degree to about +10 degree. The upper polarizeris disposed over the upper substrate. The upper polarizer includes anabsorption axis forming at an angle of about 37 degree to about 57degree in a clockwise direction with respect to a major axis of a liquidcrystal of the liquid crystal layer, and the liquid crystal is disposedadjacent to the upper substrate. The upper λ/2 retardation film isdisposed between the upper substrate and the upper polarizer. The upperλ/2 retardation film includes a first optical characteristics Δnd1 ofabout 250 nm to about 270 nm. A slow axis of the upper λ/2 retardationfilm forms at an angle of about 156 degree to about 176 degree in theclockwise direction with respect to the absorption axis. The upper λ/4retardation film is disposed between the upper substrate and the upperλ/2 retardation film. The upper λ/4 retardation film includes a secondoptical characteristics Δnd2 of about 130 nm to about 150 nm. A slowaxis of the upper λ/4 retardation film forms at an angle of about 101degree to about 121 degree in the clockwise direction with respect tothe absorption axis. Here, ‘Δn’, ‘d1’ and ‘d2’ denote an anisotropy of arefractive index, a thickness of the upper λ/2 retardation film and athickness of the upper λ/4 retardation film, respectively.

The liquid crystal display apparatus in accordance with another aspectof the present invention includes a liquid crystal display panel, alower polarizer, a lower λ/2 retardation film and a lower λ/4retardation film. The liquid crystal display panel includes an uppersubstrate, a lower substrate and a liquid crystal layer disposed betweenthe upper and lower substrates to have a twist angle of about −10 degreeto about +10 degree. The lower polarizer is disposed under the lowersubstrate. The lower polarizer includes an absorption axis forming at anangle of about 38 degree to about 58 degree in a clockwise directionwith respect to a major axis of a liquid crystal of the liquid crystallayer, and the liquid crystal is disposed adjacent to the lowersubstrate. The lower λ/2 retardation film is disposed between the lowersubstrate and the lower polarizer. The lower λ/2 retardation filmincludes a first optical characteristics Δnd1 of about 260 nm to about280 nm. A slow axis of the lower λ/2 retardation film forms at an angleof about 65 degree to about 85 degree in the clockwise direction withrespect to the absorption axis. The lower λ/4 retardation film isdisposed between the lower substrate and the lower λ/2 retardation film.The lower λ/4 retardation film includes a second optical characteristicsΔnd2 of about 120 nm to about 140 nm. A slow axis of the lower λ/4retardation film forms at an angle of about −1 degree to about 19 degreein the clockwise direction with respect to the absorption axis. Here,‘Δn’, ‘d1’ and ‘d2’ denote an anisotropy of a refractive index, athickness of the lower λ/2 retardation film and a thickness of the lowerλ/4 retardation film, respectively.

The liquid crystal display apparatus in accordance with still anotheraspect of the present invention includes a liquid crystal display panel,a lower polarizer, a lower λ/2 retardation film and a lower λ/4retardation film. The liquid crystal display panel includes an uppersubstrate, a lower substrate and a liquid crystal layer disposed betweenthe upper and lower substrates to have a twist angle of about −10 degreeto about +10 degree. The lower polarizer is disposed under the lowersubstrate. The lower polarizer includes an absorption axis forming at anangle of about 132 degree to about 152 degree in a clockwise directionwith respect to a major axis of a liquid crystal of the liquid crystallayer, and the liquid crystal is disposed adjacent to the lowersubstrate. The lower λ/2 retardation film is disposed between the lowersubstrate and the lower polarizer. The lower λ/2 retardation filmincludes a first optical characteristics Δnd1 of about 260 nm to about280 nm. A slow axis of the lower λ/2 retardation film forms at an angleof about 95 degree to about 115 degree in the clockwise direction withrespect to the absorption axis. The lower λ/4 retardation film isdisposed between the lower substrate and the lower λ/2 retardation film.The lower λ/4 retardation film includes a second optical characteristicsΔnd2 of about 120 nm to about 140 nm. A slow axis of the lower λ/4retardation film forms at an angle of about 161 degree to about 181degree in the clockwise direction with respect to the absorption axis.Here, ‘Δn’, ‘d1’ and ‘d2’ denote an anisotropy of a refractive index, athickness of the lower λ/2 retardation film and a thickness of the lowerλ/4 retardation film, respectively.

The liquid crystal display apparatus in accordance with still anotheraspect of the present invention includes a liquid crystal display panel,an upper polarizer, an upper λ/2 retardation film and an upper λ/4retardation film. The liquid crystal display panel includes an uppersubstrate, a lower substrate corresponding to the upper substrate and aliquid crystal layer disposed between the upper and lower substrates tohave a viewing angle of about 170 degree to about 250 degree in a clockdirection with respect to a horizontal direction of the liquid crystaldisplay panel and a twist angle of about −10 degree to about +10 degree.The upper polarizer is disposed over the upper substrate. The upperpolarizer includes an absorption axis forming at an angle of about 67degree to about 87 degree in the clockwise direction with respect to thehorizontal direction of the liquid crystal display panel. The upper λ/2retardation film is disposed between the upper substrate and the upperpolarizer. The upper λ/2 retardation film includes a first opticalcharacteristics Δnd1 of about 250 nm to about 270 nm. A slow axis of theupper λ/2 retardation film forms at an angle of about 81 degree to about101 degree in the clockwise direction with respect to the horizontaldirection. The upper λ/4 retardation film is disposed between the uppersubstrate and the upper λ/2 retardation film. The upper λ/4 retardationfilm includes a second optical characteristics Δnd2 of about 130 nm toabout 150 nm. A slow axis of the upper λ/4 retardation film forms at anangle of about 136 degree to about 156 degree in the clockwise directionwith respect to the horizontal direction. Here, ‘Δn’, ‘d1’ and ‘d2’denote an anisotropy of a refractive index, a thickness of the upper λ/2retardation film and a thickness of the upper λ/4 retardation film,respectively.

The liquid crystal display apparatus in accordance with still anotheraspect of the present invention includes a liquid crystal display panel,a lower polarizer, a lower λ/2 retardation film and a lower λ/4retardation film. The liquid crystal display panel includes an uppersubstrate, a lower substrate and a liquid crystal layer disposed betweenthe upper and lower substrates to have a viewing angle of about 170degree to about 250 degree in a clock direction with respect to ahorizontal direction of the liquid crystal display panel and a twistangle of about −10 degree to about +10 degree. The lower polarizer isdisposed under the lower substrate. The lower polarizer includes anabsorption axis forming at an angle of about 8 degree to about 28 degreein a clockwise direction with respect to the horizontal direction of theliquid crystal display panel. The lower λ/2 retardation film is disposedbetween the lower substrate and the lower polarizer. The lower λ/2retardation film includes a first optical characteristics Δnd1 of about260 nm to about 280 nm. A slow axis of the lower λ/2 retardation filmforms at an angle of about 113 degree to about 133 degree in theclockwise direction with respect to the horizontal direction. The lowerλ/4 retardation film is disposed between the lower substrate and thelower λ/2 retardation film. The lower λ/4 retardation film includes asecond optical characteristics Δnd2 of about 120 nm to about 140 nm. Aslow axis of the lower λ/4 retardation film forms at an angle of about−1 degree to about 19 degree in the clockwise direction with respect tothe horizontal direction. Here, ‘Δn’, ‘d1’ and ‘d2’ denote an anisotropyof a refractive index, a thickness of the lower λ/2 retardation film anda thickness of the lower λ/4 retardation film, respectively.

The liquid crystal display apparatus in accordance with still anotheraspect of the present invention includes a liquid crystal display panel,a lower polarizer, a lower λ/2 retardation film and a lower λ/4retardation film. The liquid crystal display panel includes an uppersubstrate, a lower substrate and a liquid crystal layer disposed betweenthe upper and lower substrates to have a viewing angle of about 170degree to about 250 degree in a clock direction with respect to ahorizontal direction of the liquid crystal display panel and a twistangle of about −10 degree to about +10 degree. The lower polarizer isdisposed under the lower substrate. The lower polarizer includes anabsorption axis forming at an angle of about 152 degree to about 172degree in a clockwise direction with respect to the horizontal directionof the liquid crystal display panel. The lower λ/2 retardation film isdisposed between the lower substrate and the lower polarizer. The lowerλ/2 retardation film includes a first optical characteristics Δnd1 ofabout 260 nm to about 280 nm. A slow axis of the lower λ/2 retardationfilm forms at an angle of about 47 degree to about 67 degree in theclockwise direction with respect to the horizontal direction. The lowerλ/4 retardation film is disposed between the lower substrate and thelower λ/2 retardation film. The lower λ/4 retardation film includes asecond optical characteristics Δnd2 of about 120 nm to about 140 nm. Aslow axis of the lower λ/4 retardation film forms at an angle of about161 degree to about 181 degree in the clockwise direction with respectto the horizontal direction. Here, ‘Δn’, ‘d1’ and ‘d2’ denote ananisotropy of a refractive index, a thickness of the lower λ/2retardation film and a thickness of the lower λ/4 retardation film,respectively.

The liquid crystal display apparatus in accordance with still anotheraspect of the present invention includes a liquid crystal display panel,a lower polarizer, a lower λ/2 retardation film, a lower λ/4 retardationfilm, an upper polarizer, an upper λ/2 retardation film and an upper λ/4retardation film. The liquid crystal display panel includes an uppersubstrate, a lower substrate and a liquid crystal layer disposed betweenthe upper and lower substrates to have a viewing angle of about 170degree to about 250 degree in a clock direction with respect to ahorizontal direction of the liquid crystal display panel and a twistangle of about −10 degree to about +10 degree. The lower polarizer isdisposed under the lower substrate. The lower polarizer includes a firstabsorption axis forming at an angle of about 8 degree to about 28 degreein a clockwise direction with respect to the horizontal direction of theliquid crystal display panel. The lower λ/2 retardation film is disposedbetween the lower substrate and the lower polarizer. The lower λ/2retardation film includes a first optical characteristics Δnd1 of about260 nm to about 280 nm. A slow axis of the lower λ/2 retardation filmforms at an angle of about 113 degree to about 133 degree in theclockwise direction with respect to the horizontal direction. The lowerλ/4 retardation film is disposed between the lower substrate and thelower λ/2 retardation film. The lower λ/4 retardation film includes asecond optical characteristics Δnd2 of about 120 nm to about 140 nm. Aslow axis of the lower λ/4 retardation film forms at an angle of about−1 degree to about 19 degree in the clockwise direction with respect tothe horizontal direction. The upper polarizer is disposed over the uppersubstrate of the liquid crystal display panel. The upper polarizerincludes a second absorption axis forming at an angle of about 67 degreeto about 87 degree in the clockwise direction with respect to thehorizontal direction of the liquid crystal display panel. The upper λ/2retardation film disposed between the upper substrate and the upperpolarizer. The upper λ/2 retardation film includes a third opticalcharacteristics Δnd3 of about 250 nm to about 270 nm. A slow axis of theupper λ/2 retardation film forms at an angle of about 81 degree to about101 degree in the clockwise direction with respect to the horizontaldirection. The upper λ/4 retardation film is disposed between the uppersubstrate and the upper λ/2 retardation film. The upper λ/4 retardationfilm includes a fourth optical characteristics Δnd4 of about 130 nm toabout 150 nm. A slow axis of the upper λ/4 retardation film forms at anangle of about 136 degree to about 156 degree in the clockwise directionwith respect to the horizontal direction. Here, ‘Δn’, ‘d1’, ‘d2’, ‘d3’and ‘d4’ denote an anisotropy of a refractive index, a thickness of thelower λ/2 retardation film, a thickness of the lower λ/4 retardationfilm, a thickness of the upper λ/2 retardation film and a thickness ofthe upper λ/4 retardation film, respectively.

The liquid crystal display apparatus in accordance with still anotheraspect of the present invention includes a liquid crystal display panel,an upper polarizer, an upper λ/2 retardation film and an upper λ/4retardation film. The liquid crystal display panel includes an uppersubstrate, a lower substrate corresponding to the upper substrate and aliquid crystal layer disposed between the upper and lower substrates tohave a twist angle of about 62 degree to about 82 degree. The upperpolarizer is disposed over the upper substrate. The upper λ/2retardation film is disposed between the upper substrate and the upperpolarizer. The upper λ/2 retardation film includes a first opticalcharacteristics Δnd1 of about 250 nm to about 270 nm. A slow axis of theupper λ/2 retardation film forms at an angle of about 6 degree to about26 degree in a clockwise direction with respect to an absorption axis ofthe upper polarizer. The upper λ/4 retardation film is disposed betweenthe upper substrate and the upper λ/2 retardation film. The upper λ/4retardation film includes a second optical characteristics Δnd2 of about130 nm to about 150 nm. A slow axis of the upper λ/4 retardation filmforms at an angle of about 64 degree to about 84 degree in the clockwisedirection with respect to the absorption axis. Here, ‘Δn’, ‘d1’ and ‘d2’denote an anisotropy of a refractive index, a thickness of the upper λ/2retardation film and a thickness of the upper λ/4 retardation film,respectively.

The liquid crystal display apparatus in accordance with still anotheraspect of the present invention includes a liquid crystal display panel,an upper polarizer, an upper λ/2 retardation film and an upper λ/4retardation film. The liquid crystal display panel includes an uppersubstrate, a lower substrate corresponding to the upper substrate and aliquid crystal layer disposed between the upper and lower substrates tohave a twist angle of about 50 degree to about 70 degree. The upperpolarizer is disposed over the upper substrate. The upper λ/2retardation film is disposed between the upper substrate and the upperpolarizer. The upper λ/2 retardation film includes a first opticalcharacteristics Δnd1 of about 250 nm to about 270 nm. A slow axis of theupper λ/2 retardation film forms at an angle of about 94 degree to about114 degree in a clockwise direction with respect to an absorption axisof the upper polarizer. The upper λ/4 retardation film is disposedbetween the upper substrate and the upper λ/2 retardation film. Theupper λ/4 retardation film includes a second optical characteristicsΔnd2 of about 130 nm to about 150 nm. A slow axis of the upper λ/4retardation film forms at an angle of about 159 degree to about 179degree in the clockwise direction with respect to the absorption axis.Here, ‘Δn’, ‘d1’ and ‘d2’ denote an anisotropy of a refractive index, athickness of the upper λ/2 retardation film and a thickness of the upperλ/4 retardation film, respectively.

The liquid crystal display apparatus in accordance with still anotheraspect of the present invention includes a liquid crystal display panel,an upper polarizer, an upper λ/2 retardation film and an upper λ/4retardation film. The liquid crystal display panel includes an uppersubstrate, a lower substrate corresponding to the upper substrate and aliquid crystal layer disposed between the upper and lower substrates tohave a twist angle of about 50 degree to about 70 degree. The upperpolarizer is disposed over the upper substrate. The upper λ/2retardation film is disposed between the upper substrate and the upperpolarizer. The upper λ/2 retardation film includes a first opticalcharacteristics Δnd1 of about 250 nm to about 270 nm. A slow axis of theupper λ/2 retardation film forms at angle of about 97 degree to about117 degree in a clockwise direction with respect to an absorption axisof the upper polarizer. The upper λ/4 retardation film is disposedbetween the upper substrate and the upper λ/2 retardation film. Theupper λ/4 retardation film includes a second optical characteristicsΔnd2 of about 130 nm to about 150 nm. A slow axis of the upper λ/4retardation film forms at an angle of about 164 degree to about 184degree in the clockwise direction with respect to the absorption axis.Here, ‘Δn’, ‘d1’ and ‘d2’ denote an anisotropy of a refractive index, athickness of the upper λ/2 retardation film and a thickness of the upperλ/4 retardation film, respectively.

The liquid crystal display apparatus in accordance with still anotheraspect of the present invention includes a liquid crystal display panel,an upper polarizer, an upper λ/2 retardation film and an upper λ/4retardation film. The liquid crystal display panel includes an uppersubstrate, a lower substrate corresponding to the upper substrate and aliquid crystal layer disposed between the upper and lower substrates tohave a viewing angle of about 170 degree to about 250 degree in a clockdirection with respect to a horizontal direction of the liquid crystaldisplay panel and a twist angle of about 50 degree to about 70 degree.The upper polarizer is disposed over the upper substrate. The upperpolarizer includes an absorption axis forming at an angle of about 100degree to about 120 degree in the clockwise direction with respect tothe horizontal direction of the liquid crystal display panel. The upperλ/2 retardation film is disposed between the upper substrate and theupper polarizer. The upper λ/2 retardation film includes a first opticalcharacteristics Δnd1 of about 250 nm to about 270 nm. A slow axis of theupper λ/2 retardation film forms at an angle of about 27 degree to about47 degree in the clockwise direction with respect to the horizontaldirection. The upper λ/4 retardation film is disposed between the uppersubstrate and the upper λ/2 retardation film. The upper λ/4 retardationfilm includes a second optical characteristics Δnd2 of about 130 nm toabout 150 nm. A slow axis of the upper λ/4 retardation film forms at anangle of about 94 degree to about 114 degree in the clockwise directionwith respect to the horizontal direction. Here, ‘Δn’, ‘d1’ and ‘d2’denote an anisotropy of a refractive index, a thickness of the upper λ/2retardation film and a thickness of the upper λ/4 retardation film,respectively.

The liquid crystal display apparatus in accordance with still anotheraspect of the present invention includes a liquid crystal display panel,an upper polarizer, an upper λ/2 retardation film and an upper λ/4retardation film. The liquid crystal display panel including an uppersubstrate, a lower substrate corresponding to the upper substrate and aliquid crystal layer disposed between the upper and lower substrates tohave a viewing angle of about 230 degree to about 310 degree in a clockdirection with respect to a horizontal direction of the liquid crystaldisplay panel and a twist angle of about 62 degree to about 82 degree.The upper polarizer is disposed over the upper substrate. The upperpolarizer includes an absorption axis forming at an angle of about 140degree to about 160 degree in the clockwise direction with respect tothe horizontal direction of the liquid crystal display panel. The upperλ/2 retardation film is disposed between the upper substrate and theupper polarizer. The upper λ/2 retardation film includes a first opticalcharacteristics Δnd1 of about 250 nm to about 270 nm. A slow axis of theupper λ/2 retardation film forms at an angle of about 156 degree toabout 176 degree in the clockwise direction with respect to thehorizontal direction. The upper λ/4 retardation film is disposed betweenthe upper substrate and the upper λ/2 retardation film. The upper λ/4retardation film includes a second optical characteristics Δnd2 of about130 nm to about 150 nm. A slow axis of the upper λ/4 retardation filmforms at an angle of about 34 degree to about 54 degree in the clockwisedirection with respect to the horizontal direction. Here, ‘Δn’, ‘d1’ and‘d2’ denote an anisotropy of a refractive index, a thickness of theupper λ/2 retardation film and a thickness of the upper λ/4 retardationfilm, respectively.

The liquid crystal display apparatus in accordance with still anotheraspect of the present invention includes a liquid crystal display panel,an upper polarizer, an upper λ/2 retardation film and an upper λ/4retardation film. The liquid crystal display panel includes an uppersubstrate, a lower substrate corresponding to the upper substrate and aliquid crystal layer disposed between the upper and lower substrates tohave a viewing angle of about 170 degree to about 250 degree in a clockdirection with respect to a horizontal direction of the liquid crystaldisplay panel and a twist angle of about 50 degree to about 70 degree.The upper polarizer is disposed over the upper substrate. The upperpolarizer includes an absorption axis forming at an angle of about 114degree to about 134 degree in the clockwise direction with respect tothe horizontal direction of the liquid crystal display panel. The upperλ/2 retardation film is disposed between the upper substrate and theupper polarizer. The upper λ/2 retardation film includes a first opticalcharacteristics Δnd1 of about 250 nm to about 270 nm. A slow axis of theupper λ/2 retardation film forms at an angle of about 38 degree to about58 degree in the clockwise direction with respect to the horizontaldirection. The upper λ/4 retardation film is disposed between the uppersubstrate and the upper λ/2 retardation film. The upper λ/4 retardationfilm includes a second optical characteristics Δnd2 of about 130 nm toabout 150 nm. A slow axis of the upper λ/4 retardation film forms at anangle of about 103 degree to about 123 degree in the clockwise directionwith respect to the horizontal direction. Here, ‘Δn’, ‘d1’ and ‘d2’denote an anisotropy of a refractive index, a thickness of the upper λ/2retardation film and a thickness of the upper λ/4 retardation film,respectively.

The liquid crystal display apparatus in accordance with still anotheraspect of the present invention includes a liquid crystal display panel,a lower polarizer, a lower λ/2 retardation film, a lower λ/4 retardationfilm, an upper λ/2 retardation film and an upper λ/4 retardation film.The liquid crystal display panel includes an upper substrate, a lowersubstrate and a liquid crystal layer disposed between the upper andlower substrates to have a twist angle of about 62 degree to about 82degree. The lower polarizer is disposed under the lower substrate. Thelower λ/2 retardation film is disposed between the lower substrate andthe lower polarizer. The lower λ/2 retardation film includes a firstoptical characteristics Δnd1 of about 260 nm to about 280 nm. The lowerλ/4 retardation film is disposed between the lower substrate and thelower λ/2 retardation film. The lower λ/4 retardation film includes asecond optical characteristics Δnd2 of about 135 nm to about 155 nm. Theupper λ/2 retardation film is disposed over the upper substrate. A slowaxis of the upper λ/2 retardation film forms at an angle of about 155degree to about 175 degree in a clockwise direction with respect to anabsorption axis of the lower polarizer. The upper λ/4 retardation filmis disposed between the upper substrate and the upper λ/2 retardationfilm. A slow axis of the upper λ/4 retardation film forms at an angle ofabout 96 degree to about 116 degree in the clockwise direction withrespect to the absorption axis of the lower polarizer. Here, ‘Δn’, ‘d1’and ‘d2’ denote an anisotropy of a refractive index, a thickness of thelower λ/2 retardation film and a thickness of the lower λ/4 retardationfilm, respectively.

The liquid crystal display apparatus in accordance with still anotheraspect of the present invention includes a liquid crystal display panel,a lower polarizer, a lower λ/2 retardation film, a lower λ/4 retardationfilm, an upper λ/2 retardation film and an upper λ/4 retardation film.The liquid crystal display panel includes an upper substrate, a lowersubstrate and a liquid crystal layer disposed between the upper andlower substrates to have a twist angle of about 50 degree to about 70degree. The lower polarizer is disposed under the lower substrate. Thelower λ/2 retardation film is disposed between the lower substrate andthe lower polarizer. The lower λ/2 retardation film includes a firstoptical characteristics Δnd1 of about 260 nm to about 280 nm. The lowerλ/4 retardation film is disposed between the lower substrate and thelower λ/2 retardation film. The lower λ/4 retardation film includes asecond optical characteristics Δnd2 of about 130 nm to about 150 nm. Theupper λ/2 retardation film is disposed over the upper substrate. A slowaxis of the upper λ/2 retardation film forms at an angle of about 28degree to about 48 degree in a clockwise direction with respect to anabsorption axis of the lower polarizer. The upper λ/4 retardation filmis disposed between the upper substrate and the upper λ/2 retardationfilm. A slow axis of the upper λ/4 retardation film forms at an angle ofabout 94 degree to about 114 degree in the clockwise direction withrespect to the absorption axis of the lower polarizer. Here, ‘Δn’, ‘d1’and ‘d2’ denote an anisotropy of a refractive index, a thickness of thelower λ/2 retardation film and a thickness of the lower λ/4 retardationfilm, respectively.

The liquid crystal display apparatus in accordance with still anotheraspect of the present invention includes a liquid crystal display panel,a lower polarizer, a lower λ/2 retardation film and a lower λ/4retardation film. The liquid crystal display panel includes an uppersubstrate, a lower substrate corresponding to the upper substrate and aliquid crystal layer disposed between the upper and lower substrates tohave a twist angle of about 50 degree to about 70 degree. The lowerpolarizer is disposed under the lower substrate. The lower λ/2retardation film is disposed between the lower substrate and the lowerpolarizer. The lower λ/2 retardation film includes a first opticalcharacteristics Δnd1 of about 260 nm to about 280 nm. A slow axis of thelower λ/2 retardation film forms at an angle of about 1 degree to about21 degree in a clockwise direction with respect to an absorption axis ofthe lower polarizer. The lower λ/4 retardation film is disposed betweenthe lower substrate and the lower λ/2 retardation film. The lower λ/4retardation film includes a second optical characteristics Δnd2 of about130 nm to about 150 nm. A slow axis of the lower λ/4 retardation filmforms at an angle of about 59 degree to about 79 degree in the clockwisedirection with respect to the absorption axis. Here, ‘Δn’, ‘d1’ and ‘d2’denote an anisotropy of a refractive index, a thickness of the lower λ/2retardation film and a thickness of the lower λ/4 retardation film,respectively.

The liquid crystal display apparatus in accordance with still anotheraspect of the present invention includes a liquid crystal display panel,a lower polarizer, a lower λ/2 retardation film and a lower λ/4retardation film. The liquid crystal display panel includes an uppersubstrate, a lower substrate corresponding to the upper substrate and aliquid crystal layer disposed between the upper and lower substrates tohave a viewing angle of about 230 degree to about 310 degree in a clockdirection with respect to a horizontal direction of the liquid crystaldisplay panel and a twist angle of about 62 degree to about 82 degree.The lower polarizer is disposed over the lower substrate. The lowerpolarizer includes an absorption axis forming at an angle of about 110degree to about 130 degree in the clockwise direction with respect tothe horizontal direction of the liquid crystal display panel. The lowerλ/2 retardation film is disposed between the lower substrate and thelower polarizer. The lower λ/2 retardation film includes a first opticalcharacteristics Δnd1 of about 260 nm to about 280 nm. A slow axis of thelower λ/2 retardation film forms at an angle of about 95 degree to about115 degree in the clockwise direction with respect to the horizontaldirection. The lower λ/4 retardation film is disposed between the lowersubstrate and the lower λ/2 retardation film. The lower λ/4 retardationfilm includes a second optical characteristics Δnd2 of about 135 nm toabout 155 nm. A slow axis of the lower λ/4 retardation film forms at anangle of about 36 degree to about 56 degree in the clockwise directionwith respect to the horizontal direction. Here, ‘Δn’, ‘d1’ and ‘d2’denote an anisotropy of a refractive index, a thickness of the lower λ/2retardation film and a thickness of the lower λ/4 retardation film,respectively.

The liquid crystal display apparatus in accordance with still anotheraspect of the present invention includes a liquid crystal display panel,a lower polarizer, a lower λ/2 retardation film and a lower λ/4retardation film. The liquid crystal display panel includes an uppersubstrate, a lower substrate corresponding to the upper substrate and aliquid crystal layer disposed between the upper and lower substrates tohave a viewing angle of about 170 degree to about 250 degree in a clockdirection with respect to a horizontal direction of the liquid crystaldisplay panel and a twist angle of about 50 degree to about 70 degree.The lower polarizer is disposed over the lower substrate. The lowerpolarizer includes an absorption axis forming at an angle of about 136degree to about 156 degree in the clockwise direction with respect tothe horizontal direction of the liquid crystal display panel. The lowerλ/2 retardation film is disposed between the lower substrate and thelower polarizer. The lower λ/2 retardation film includes a first opticalcharacteristics Δnd1 of about 260 nm to about 280 nm. A slow axis of thelower λ/2 retardation film forms at an angle of about 152 degree toabout 172 degree in the clockwise direction with respect to thehorizontal direction. The lower λ/4 retardation film is disposed betweenthe lower substrate and the lower λ/2 retardation film. The lower λ/4retardation film includes a second optical characteristics Δnd2 of about130 nm to about 150 nm. A slow axis of the lower λ/4 retardation filmforms at an angle of about 38 degree to about 58 degree in the clockwisedirection with respect to the horizontal direction. Here, ‘Δn’, ‘d1’ and‘d2’ denote an anisotropy of a refractive index, a thickness of thelower λ/2 retardation film and a thickness of the lower λ/4 retardationfilm, respectively.

The liquid crystal display apparatus in accordance with still anotheraspect of the present invention includes a liquid crystal display panel,a lower polarizer, a lower λ/2 retardation film and a lower λ/4retardation film. The liquid crystal display panel includes an uppersubstrate, a lower substrate corresponding to the upper substrate and aliquid crystal layer disposed between the upper and lower substrates tohave a viewing angle of about 170 degree to about 250 degree in a clockdirection with respect to a horizontal direction of the liquid crystaldisplay panel and a twist angle of about 50 degree to about 70 degree.The lower polarizer is disposed over the lower substrate. The lowerpolarizer includes an absorption axis forming at an angle of about 150degree to about 170 degree in the clockwise direction with respect tothe horizontal direction of the liquid crystal display panel. The lowerλ/2 retardation film is disposed between the lower substrate and thelower polarizer. The lower λ/2 retardation film includes a first opticalcharacteristics Δnd1 of about 260 nm to about 280 nm. A slow axis of thelower λ/2 retardation film forms at an angle of about 161 degree toabout 181 degree in the clockwise direction with respect to thehorizontal direction. The lower λ/4 retardation film is disposed betweenthe lower substrate and the lower λ/2 retardation film. The lower λ/4retardation film includes a second optical characteristics Δnd2 of about130 nm to about 150 nm. A slow axis of the lower λ/4 retardation filmforms at an angle of about 39 degree to about 59 degree in the clockwisedirection with respect to the horizontal direction. Here, ‘Δn’, ‘d1’ and‘d2’ denote an anisotropy of a refractive index, a thickness of thelower λ/2 retardation film and a thickness of the lower λ/4 retardationfilm, respectively.

The LCD apparatus includes a reflective type LCD apparatus, atransmissive type LCD apparatus or a transmissive-reflective type LCDapparatus having a multi-cell gap.

Therefore, the optical conditions of the optical film assembly and theLCD apparatus are optimized to improve the light transmittance, thecontrast ratio and the viewing angle of the LCD apparatus. In addition,the viewing angle is uniformized.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other advantages of the present invention will become moreapparent by describing in detail exemplary embodiments thereof withreference to the accompanying drawings, in which:

FIG. 1 is a cross-sectional view showing a transmissive-reflective typeliquid crystal display (LCD) apparatus in accordance with an exemplaryembodiment of the present invention;

FIG. 2 is a graph showing a relationship between a luminance and avoltage applied to the LCD apparatus shown in FIG. 1;

FIG. 3 is an exploded perspective view showing a transmissive-reflectivetype LCD apparatus in accordance with an exemplary embodiment of thepresent invention;

FIG. 4 is a graph showing a relationship between a luminance and aviewing angle when the LCD apparatus shown in FIG. 3 displays blackcolor;

FIG. 5 is a graph showing a relationship between a luminance and aviewing angle when the LCD apparatus shown in FIG. 3 displays whitecolor;

FIG. 6 is a graph showing a relationship between a contrast ratio and aviewing angle of the LCD apparatus shown in FIG. 3;

FIG. 7 is a cross-sectional view showing an LCD apparatus in accordancewith another exemplary embodiment of the present invention;

FIG. 8 is an exploded perspective view showing an LCD apparatus inaccordance with another exemplary embodiment of the present invention;

FIG. 9 is an exploded perspective view showing an LCD apparatus inaccordance with another exemplary embodiment of the present invention;

FIG. 10 is an exploded perspective view showing an LCD apparatus inaccordance with another exemplary embodiment of the present invention;

FIGS. 11 and 12 are graphs showing a relationship between a luminanceand a viewing angle when an LCD apparatus in accordance with anotherexemplary embodiment of the present invention displays black color;

FIGS. 13 and 14 are graphs showing a relationship between a luminanceand a viewing angle when an LCD apparatus in accordance with anotherexemplary embodiment of the present invention displays white color;

FIGS. 15 and 16 are graphs showing a relationship between a contrastratio and a viewing angle of an LCD apparatus in accordance with anotherexemplary embodiment of the present invention;

FIG. 17 is a cross-sectional view showing an LCD apparatus in accordancewith another exemplary embodiment of the present invention;

FIG. 18 is an exploded perspective view showing an upper optical filmassembly of the LCD apparatus shown in FIG. 17;

FIG. 19 is an exploded perspective view showing a lower optical filmassembly of the LCD apparatus shown in FIG. 17;

FIG. 20 is a cross-sectional view showing a reflection mode of the LCDapparatus shown in FIG. 17;

FIG. 21 is a cross-sectional view showing a transmission mode of the LCDapparatus shown in FIG. 17;

FIGS. 22 and 23 are graphs showing a relationship between a luminanceand a viewing angle when an LCD apparatus in accordance with anotherexemplary embodiment of the present invention displays black color;

FIGS. 24 and 25 are graphs showing a relationship between a luminanceand a viewing angle when an LCD apparatus in accordance with anotherexemplary embodiment of the present invention displays white color; and

FIGS. 26 and 27 are graphs showing a relationship between a contrastratio and a viewing angle of an LCD apparatus in accordance with anotherexemplary embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

It should be understood that the exemplary embodiments of the presentinvention described below may be varied modified in many different wayswithout departing from the inventive principles disclosed herein, andthe scope of the present invention is therefore not limited to theseparticular following embodiments. Rather, these embodiments are providedso that this disclosure will be through and complete, and will fullyconvey the concept of the invention to those skilled in the art by wayof example and not of limitation.

Hereinafter, the present invention will be described in detail withreference to the accompanying drawings.

FIG. 1 is a cross-sectional view showing a transmissive-reflective typeliquid crystal display (LCD) apparatus in accordance with an exemplaryembodiment of the present invention.

Referring to FIG. 1, the transmissive-reflective type LCD apparatus 10includes a lower polarizer 11, a lower λ/2 retardation film 12 disposedon the lower polarizer 11, a lower λ/4 retardation film 13 disposed onthe lower λ/2 retardation film 12, a reflecting plate 14 disposed on thelower λ/4 retardation film 13, a liquid crystal layer 15 disposed on thereflecting plate 14, a color filter 16 disposed on the liquid crystallayer 15, an upper λ/4 retardation film 17 disposed on the color filter16, an upper λ/2 retardation film 18 disposed on the upper λ/4retardation film 17 and an upper polarizer 19 disposed on the upper λ/2retardation film 18. When a linearly polarized light passes through theretardation films 12, 13, 17 and 18, the linearly polarized light may beconverted into an elliptically polarized light or a circularly polarizedlight. Also, when the elliptically polarized light or the circularlypolarized light passes through the retardation films 12, 13, 17 and 18,the elliptically polarized light or the circularly polarized light maybe converted into the linearly polarized light. In addition, when thelinearly polarized light passes through the retardation films 12, 13, 17and 18, the direction of the linearly polarized light may be changed. Inparticular, when the linearly polarized light passes through the λ/2retardation films 12 and 18, the direction of the linearly polarizedlight is changed. In addition, when the linearly polarized light and thecircularly polarized light pass through the λ/4 retardation films 13 and17, the linearly polarized light and the circularly polarized light areconverted into the circularly polarized light and the linearly polarizedlight, respectively.

In a transmission mode, an artificial light passes through the lowerpolarizer 11, the lower λ/2 retardation film 12, the lower λ/4retardation film 13, the liquid crystal layer 15, the color filter 16,the upper λ/4 retardation film 17, the upper λ/2 retardation film 18 andthe upper polarizer 19, in sequence, to display the image.

In a reflection mode, a natural light passes through the upper polarizer19, the upper λ/2 retardation film 18, the upper λ/4 retardation film17, the color filter 16 and the liquid crystal layer 15, in sequence, sothat the natural light that passes through the liquid crystal layer 15is reflected from the reflecting plate 14. The reflected light passesthrough the liquid crystal layer 15, the color filter 16, the upper λ/4retardation film 17, the upper λ/2 retardation film 18 and the upperpolarizer 19, in sequence, to display the image.

FIG. 2 is a graph showing a relationship between a luminance and avoltage applied to the LCD apparatus shown in FIG. 1.

Referring to FIG. 2, when the LCD apparatus includes a normally whitemode and a low voltage is applied to the LCD apparatus, the LCDapparatus displays white color. When the LCD apparatus includes thenormally white mode and a high voltage that is higher than a drivingvoltage of the liquid crystal layer 15 is applied to the LCD apparatus,the LCD apparatus displays black color. A shape of a curve showing arelationship between a voltage applied to the LCD apparatus and aluminance of the transmission mode is substantially similar to that of acurve showing a relationship between the voltage applied to the LCDapparatus and a luminance of the reflection mode.

FIG. 3 is an exploded perspective view showing a transmissive-reflectivetype LCD apparatus in accordance with an exemplary embodiment of thepresent invention. A reference direction of an LCD panel of the LCDapparatus is a horizontal direction with respect to the LCD panel. Areference wavelength of a light is about 550 nm.

Referring to FIG. 3, the liquid crystal layer 15 (shown in FIG. 1) isdisposed between an array substrate 15T and a color filter substrate15C. An anisotropy Δn of a reflective index of the liquid crystal layer15 is about 0.078 ZSM5342 with reference to a light having a wavelengthof about 589 nm. The ‘ZSM5342’ is a unit of the anisotropy Δn of thereflective index. A thickness d1 of the liquid crystal layer 15 is about3.0 μm. A twist angle of the liquid crystal layer 15 is about 72 degree.A viewing angle of the liquid crystal layer 15 is about 8 degree. Adirection of a major axis of a liquid crystal of the liquid crystallayer 15, and the liquid crystal is disposed adjacent to the lowersubstrate may be the reference direction. The upper λ/4 retardation film17 is disposed on the color filter substrate 15C. A second opticalcharacteristics Δnd2 of the upper λ/4 retardation film 17 is about 140nm with reference to a reference light whose wavelength is about 550 nm.A slow axis of the upper λ/4 retardation film 17 forms at an angle ofabout 74 degree with respect to the reference direction in a clockwisedirection. A velocity of the light that passes through the upper λ/4retardation film 17 along the slow axis is slower than that of the lightthat passes through the upper λ/4 retardation film 17 along a fast axis.The upper λ/2 retardation film 18 is disposed on the upper λ/4retardation film 17. A third optical characteristics Δnd3 of the upperλ/2 retardation film 18 is about 260 nm with reference to the referencelight whose wavelength is about 550 nm. A slow axis of the upper λ/2retardation film 18 forms at an angle of about 156 degree to about 176degree with respect to the reference direction in a clockwise direction.The upper polarizer 19 is disposed on the upper λ/2 retardation film 18.An absorption axis of the upper polarizer 19 forms at an angle of about140 degree to about 160 degree with respect to the reference directionof the LCD panel in the clockwise direction.

The lower λ/4 retardation film 13 is disposed under the array substrate15T. A fourth optical characteristics Δnd4 of the lower λ/4 retardationfilm 13 is about 145 nm with respect to the reference wavelength. A slowaxis of the lower λ/4 retardation film 13 forms at an angle of about 46degree with respect to the reference direction in the clockwisedirection. The lower λ/2 retardation film 12 is disposed under the lowerλ/4 retardation film 13. A fifth optical characteristics Δnd5 of thelower λ/2 retardation film 12 is about 270 nm with respect to thereference wavelength. A slow axis of the lower λ/2 retardation film 12forms at an angle of about 105 degree with respect to the referencedirection in the clockwise direction. The lower polarizer 11 is disposedunder the lower λ/2 retardation film 12. An absorption axis of the lowerpolarizer 11 forms at an angle of about 120 degree with respect to thereference direction in the clockwise direction.

FIG. 4 is a graph showing a relationship between a luminance and aviewing angle when the LCD apparatus shown in FIG. 3 displays blackcolor. FIG. 5 is a graph showing a relationship between a luminance anda viewing angle when the LCD apparatus shown in FIG. 3 displays whitecolor. FIG. 6 is a graph showing a relationship between a contrast ratioand a viewing angle of the LCD apparatus shown in FIG. 3.

Referring to FIG. 4, the black color is displayed in a direction at anangle of about 90 degree with respect to the reference direction in theclockwise direction. The black color is not displayed in a direction atan angle of about 90 degree with respect to the reference direction in acounter-clockwise direction. In particular, the white color having aluminance of about 17.5 [Cd/m³] is displayed in a direction at an angleof about 60 degree to about 80 degree with respect to the referencedirection in the counter-clockwise direction.

Referring to FIG. 5, the white color is displayed in a directionsubstantially perpendicular to the reference direction.

Referring to FIG. 6, an image having high contrast ratio is displayed atan angle of about 90 degree with respect to the reference direction sothat a contrast ratio of an upper portion of the LCD panel is differentfrom that of a lower portion of the LCD panel.

Therefore, the display quality of the transmissive-reflective LCDapparatus having a unit cell-gap may be deteriorated.

FIG. 7 is a cross-sectional view showing an LCD apparatus in accordancewith another exemplary embodiment of the present invention. The LCDapparatus includes a transmissive-reflective LCD apparatus having a unitcell-gap and a top indium tin oxide (ITO) type.

Referring to FIG. 7, the LCD apparatus includes an array substrate 100,a color filter substrate 200, a liquid crystal layer 300, an upperoptical film assembly 400 and a lower optical film assembly 500. Theliquid crystal layer 300 is disposed between the array substrate 100 andthe color filter substrate 200. The upper optical film assembly 400 isdisposed on the color filter substrate 200. The lower optical filmassembly 500 is disposed under the array substrate 100.

The array substrate 100 includes a first transparent plate 105, aswitching element that includes a thin film transistor (TFT), apassivation layer 140 and an organic insulating layer 144. The switchingelement is formed on the first transparent plate 105. The switchingelement includes a gate electrode 110, a gate insulating layer 112 thatis formed on the first transparent plate 105 having the gate electrode110, a semiconductor layer 114, an ohmic contact layer 116, a sourceelectrode 120 and a drain electrode 130. The passivation layer 140 isformed on the first transparent plate 105 having the switching element.The passivation layer 140 includes a first opening, through which thedrain electrode 130 is partially exposed. The organic insulating layer144 is formed on the passivation layer 140. The organic insulating layer144 has a second opening, through which the drain electrode 130 ispartially exposed. The second opening is disposed on the first opening.The first and second openings form a first contact hole 141. Convex andconcave portions may be formed on the organic insulating layer 144 toimprove a reflective index of a reflecting plate 160.

The array substrate 100 further includes a pixel electrode 150, aninsulating interlayer 152 and the reflecting plate 160. The pixelelectrode 150 is electrically connected to the drain electrode 130through the first contact hole 141. The switching element is formed on aportion of the pixel electrode 130, which corresponds to the switchingelement. The reflecting plate 160 is formed on the insulating interlayer152. The array substrate 100 further includes a reflection region and atransmission window 145. The reflecting plate 160 is disposed in thereflection region. The reflecting plate 160 defines the transmissionwindow 145.

The pixel electrode 150 includes a transparent conductive material, forexample, such as indium tin oxide (ITO), tin oxide (TO), indium zincoxide (IZO), zinc oxide (ZO), etc. A capacitor line is formed at aposition spaced apart from the switching element to form a storagecapacitor (Cst, not shown). The capacitor line is disposed under thepixel electrode 150.

The reflecting plate 160 is formed on the insulating interlayer 152corresponding to the reflection region. The reflecting plate 160 iselectrically insulated from the pixel electrode 150 by the insulatinginterlayer 152. Alternatively, a portion of the insulating interlayer152 is removed so that the reflecting plate 160 is electricallyconnected to the pixel electrode 150. In addition, the insulatinginterlayer 152 may be omitted, and a conductive layer (not shown) may bedisposed between the reflecting plate 160 and the pixel electrode 150.

The color filter substrate 200 includes a second transparent plate 205,a black matrix (not shown), a color filter 210 and an overcoating layer(not shown). The black matrix is formed on the second transparent plate205 to define red (R), green (G) and blue (B) pixel regions. The colorfilter 210 is formed in the red (R), green (G) and the blue (B) pixelregions. The overcoating layer is coated on the second transparent plate205 having the black matrix and the color filter 210 to protect theblack matrix and the color filter 210. Alternatively, portions of thecolor filter 210 may be overlapped with one another to form the blackmatrix. A common electrode (not shown) may also be formed on theovercoating layer.

The liquid crystal layer 300 is formed between the array substrate 100and the color filter substrate 200. A liquid crystal of the liquidcrystal layer 300 varies an arrangement in response to an electric fieldapplied between the pixel electrode 150 of the array substrate 100 andthe common electrode of the color filter substrate 200, and thus a lighttransmittance of a natural light that passes through the color filtersubstrate 200 or an artificial light that passes through thetransmission window 145 may be changed. A direction of a major axis of aliquid crystal of the liquid crystal layer 300, which is disposedadjacent to the lower substrate, may be the reference direction.

The liquid crystal layer 300 may have a homogeneous alignment mode. Whenthe liquid crystal layer 300 has the homogeneous alignment mode, a twistangle of the liquid crystal layer 300 is about 0 degree.

The array substrate 100 may include a first alignment layer (not shown)so that the first alignment layer is rubbed in a first rubbing directionthat is in substantially parallel with a horizontal direction. The colorfilter substrate 200 may also include a second alignment layer (notshown) so that the second alignment layer is rubbed in a second rubbingdirection that is in substantially opposite to the first rubbingdirection. Alternatively, the second alignment layer may be rubbed in asecond rubbing direction that is in substantially parallel with thehorizontal direction, and the first alignment layer may be rubbed in afirst rubbing direction that is in substantially opposite to the secondrubbing direction.

In this exemplary embodiment, the array substrate 100 includes the pixelelectrode 150, and the color filter substrate 200 includes the commonelectrode. Alternatively, the LCD apparatus may include a coplanarelectrode (CE) mode, for example, such as an in-plane switching (IPS)mode, a fringe field switching (FFS) mode, etc., so that the colorfilter substrate 200 includes the common electrode.

In this exemplary embodiment, the LCD apparatus includes thetransmissive-reflective LCD apparatus. Alternatively, the LCD apparatusmay include a reflective type LCD apparatus having a switching element,a pixel electrode that is electrically connected to a drain electrode ofthe switching element and a reflecting plate that is formed on the pixelelectrode to reflect the natural light.

In this exemplary embodiment, the LCD apparatus includes the top indiumtin oxide (ITO) type. Alternatively, the LCD apparatus may include abottom ITO type. A pixel electrode of the bottom ITO type LCD apparatusis formed under the organic insulating layer.

The upper optical film assembly 400 includes an upper λ/4 retardationfilm 410 disposed on the color filter substrate 200, an upper λ/2retardation film 420 disposed on the upper λ/4 retardation film 420 andan upper polarizer 430 disposed on the upper λ/2 retardation film 420.The lower optical film assembly 500 includes a lower λ/4 retardationfilm 510 disposed under the array substrate 100, a lower λ/2 retardationfilm disposed under the lower λ/4 retardation film and a lower polarizer530 disposed under the lower λ/2 retardation film 520.

A reference direction is in substantially parallel with the horizontaldirection. A reference wavelength of the LCD apparatus is about 550 nm.A velocity of a light that passes through a retardation film along aslow axis is slower than that of a light that passes through theretardation film along a fast axis.

FIG. 8 is an exploded perspective view showing an LCD apparatus inaccordance with another exemplary embodiment of the present invention.Referring to FIG. 8 in which the same reference numerals denote the sameelements as in FIG. 3, and thus any further detailed descriptionsconcerning the same elements will be omitted. A reference direction isin substantially parallel with a horizontal direction of an LCD panel ofthe LCD apparatus.

Referring to FIG. 8, the liquid crystal layer is disposed between anarray substrate 100 and a color filter substrate 200. An anisotropy Δnof a reflective index of the liquid crystal layer is about 0.078 ZSM5342with reference to a light having a wavelength of about 589 nm. The‘ZSM5342’ is a unit of the anisotropy Δn of the reflective index. Athickness d1 of the liquid crystal layer 15 is about 3.0 μm. A twistangle of the liquid crystal layer is about 72 degree. A viewing angle ofthe liquid crystal layer is about 12 degree.

The upper λ/4 retardation film 412 is disposed on the color filtersubstrate 200. A second optical characteristics Δnd2 of the upper λ/4retardation film 412 is about 130 nm to about 150 nm with reference to areference light whose wavelength is about 550 nm. A slow axis of theupper λ/4 retardation film 412 forms at an angle of about 34 degree toabout 54 degree with respect to the reference direction in a clockwisedirection.

The upper λ/2 retardation film 422 is disposed on the upper λ/4retardation film 412. A third optical characteristics Δnd3 of the upperλ/2 retardation film 422 is about 250 nm to about 270 nm with referenceto the reference light whose wavelength is about 550 nm. A slow axis ofthe upper λ/2 retardation film 422 forms at an angle of about 156 degreeto about 176 degree with respect to the reference direction in aclockwise direction.

The upper polarizer 432 is disposed on the upper λ/2 retardation film422. An absorption axis of the upper polarizer 432 forms at an angle ofabout 140 degree to about 160 degree with respect to the referencedirection of the LCD panel in the clockwise direction.

The lower λ/4 retardation film 512 is disposed under the array substrate100. A fourth optical characteristics Δnd4 of the lower λ/4 retardationfilm 512 is about 135 nm to about 155 nm with respect to the referencewavelength. A slow axis of the lower λ/4 retardation film 512 forms atan angle of about 36 degree to about 56 degree with respect to thereference direction in the clockwise direction.

The lower λ/2 retardation film 522 is disposed under the lower λ/4retardation film 512. A fifth optical characteristics Δnd5 of the lowerλ/2 retardation film 522 is about 260 nm to about 280 nm with respect tothe reference wavelength. A slow axis of the lower λ/2 retardation film522 forms at an angle of about 95 degree to about 115 degree withrespect to the reference direction in the clockwise direction.

The lower polarizer 532 is disposed under the lower λ/2 retardation film522. An absorption axis of the lower polarizer 532 forms at an angle ofabout 110 degree to about 130 degree with respect to the referencedirection in the clockwise direction.

In another exemplary embodiment, a slow axis of a lower λ/4 retardationfilm may form at an angle of about 124 degree to about 144 degree withrespect to the reference direction in the clockwise direction. A slowaxis of a lower λ/2 retardation film may form at an angle of about 65degree to about 85 degree with respect to the reference direction in theclockwise direction. An absorption axis of a lower polarizer may form atan angle of about 50 degree to about 70 degree with respect to thereference direction in the clockwise direction.

A light transmittance of the LCD apparatus in this exemplary embodimentis about 0.2373, and a contrast ratio of a transmission mode of the LCDapparatus in this exemplary embodiment is about 911. The lighttransmittance of the LCD apparatus in this exemplary embodiment isincreased by about 20% than that of the LCD apparatus shown in FIG. 3.The contrast ratio of the transmission mode of the LCD apparatus in thisexemplary embodiment is substantially the same as that of the LCDapparatus shown in FIG. 3.

A light reflectivity of the LCD apparatus in this exemplary embodimentis about 8%, and is substantially the same as that of the LCD apparatusshown in FIG. 3. A contrast ratio of the reflection mode of the LCDapparatus in this exemplary embodiment is about 30, and is substantiallythe same as that of the LCD apparatus shown in FIG. 3. A lightreflectivity of an integrating sphere of the LCD apparatus in thisexemplary embodiment is about 5%, and is substantially the same as thatof the LCD apparatus shown in FIG. 3. A contrast ratio of theintegrating sphere of the LCD apparatus in this exemplary embodiment isabout 10, and is substantially the same as that of the LCD apparatusshown in FIG. 3.

A luminance viewed in front of the LCD panel in this exemplaryembodiment is about 70 [Cd/m³]. A luminance viewed in front of the LCDpanel shown in FIG. 3 is about 55 [Cd/m³]. The luminance viewed in frontof the LCD panel in this exemplary embodiment is increased by about 25%than that of the LCD panel shown in FIG. 3. A contrast ratio viewed infront of the LCD panel in this exemplary embodiment is about 110. Acontrast ratio viewed in front of the LCD panel shown in FIG. 3 is about80. The contrast ratio viewed in front of the LCD panel in thisexemplary embodiment is increased by about 12% than that of the LCDpanel shown in FIG. 3. Viewing angles of an upper portion, a lowerportion, a left portion and a right portion of the LCD panel in thisexemplary embodiment are about 28, 28, 52 and 22, respectively. Viewingangles of an upper portion, a lower portion, a left portion and a rightportion of the LCD panel shown in FIG. 3 are about 21, 36, 22 and 38,respectively. Therefore, the viewing angles are increased.

FIG. 9 is an exploded perspective view showing an LCD apparatus inaccordance with another exemplary embodiment of the present invention.Referring to FIG. 9 in which the same reference numerals denote the sameelements in FIG. 3, and thus any further detailed descriptionsconcerning the same elements will be omitted. A reference direction isin substantially parallel with a horizontal direction of an LCD panel ofthe LCD apparatus.

Referring to FIG. 9, the liquid crystal layer is disposed between anarray substrate 100 and a color filter substrate 200. An anisotropy Δnof a reflective index of the liquid crystal layer is about 0.078 ZSM5342with reference to a light having a wavelength of about 589 nm. The‘ZSM5342’ is a unit of the anisotropy Δn of the reflective index. Athickness d1 of the liquid crystal layer is about 3.0 μm. A twist angleof the liquid crystal layer is about 60 degree. A viewing angle of theliquid crystal layer is about 10 degree.

The upper λ/4 retardation film 414 is disposed on the color filtersubstrate 200. A second optical characteristics Δnd2 of the upper λ/4retardation film 414 is about 130 nm to about 150 nm with reference to areference light whose wavelength is about 550 nm. A slow axis of theupper λ/4 retardation film 414 forms at an angle of about 103 degree toabout 123 degree with respect to the reference direction in a clockwisedirection.

The upper λ/2 retardation film 424 is disposed on the upper λ/4retardation film 414. A third optical characteristics Δnd3 of the upperλ/2 retardation film 424 is about 250 nm to about 270 nm with referenceto the reference light whose wavelength is about 550 nm. A slow axis ofthe upper λ/2 retardation film 424 forms at an angle of about 38 degreeto about 58 degree with respect to the reference direction in aclockwise direction.

The upper polarizer 434 is disposed on the upper λ/2 retardation film424. An absorption axis of the upper polarizer 434 forms at an angle ofabout 114 degree to about 134 degree with respect to the referencedirection of the LCD panel in the clockwise direction.

The lower λ/4 retardation film 514 is disposed under the array substrate100. A fourth optical characteristics Δnd4 of the lower λ/4 retardationfilm 514 is about 120 nm to about 140 nm with respect to the referencewavelength. A slow axis of the lower λ/4 retardation film 514 forms atan angle of about 38 degree to about 58 degree with respect to thereference direction in the clockwise direction.

The lower λ/2 retardation film 524 is disposed under the lower λ/4retardation film 514. A fifth optical characteristics Δnd5 of the lowerλ/2 retardation film 524 is about 260 nm to about 280 nm with respect tothe reference wavelength. A slow axis of the lower λ/2 retardation film524 forms at an angle of about 152 degree to about 172 degree withrespect to the reference direction in the clockwise direction.

The lower polarizer 534 is disposed under the lower λ/2 retardation film524. An absorption axis of the lower polarizer 534 forms at an angle ofabout 136 degree to about 156 degree with respect to the referencedirection in the clockwise direction.

In another exemplary embodiment, a slow axis of a lower λ/4 retardationfilm may form at an angle of about 122 degree to about 142 degree withrespect to the reference direction in the clockwise direction. A slowaxis of a lower λ/2 retardation film may be form at an angle of about 8degree to about 28 degree with respect to the reference direction in theclockwise direction. An absorption axis of a lower polarizer may be format an angle of about 24 degree to about 44 degree with respect to thereference direction in the clockwise direction.

A light transmittance of the LCD apparatus in this exemplary embodimentis about 0.2838, and a contrast ratio of a transmission mode of the LCDapparatus in this exemplary embodiment is about 2247. The lighttransmittance of the LCD apparatus in this exemplary embodiment isincreased by about 250% than that of the LCD apparatus shown in FIG. 3.The contrast ratio of the transmission mode of the LCD apparatus in thisexemplary embodiment is substantially the same as that of the LCDapparatus shown in FIG. 3.

A light reflectivity of the LCD apparatus in this exemplary embodimentis about 8%, and is substantially the same as that of the LCD apparatusshown in FIG. 3. A contrast ratio of the reflection mode of the LCDapparatus in this exemplary embodiment is about 30, and is substantiallythe same as that of the LCD apparatus shown in FIG. 3. A lightreflectivity of an integrating sphere of the LCD apparatus in thisexemplary embodiment is about 5%, and is substantially the same as thatof the LCD apparatus shown in FIG. 3. A contrast ratio of theintegrating sphere of the LCD apparatus in this exemplary embodiment isabout 10, and is substantially the same as that of the LCD apparatusshown in FIG. 3.

A luminance viewed in front of the LCD panel in this exemplaryembodiment is about 85 [Cd/m³]. A luminance viewed in front of the LCDpanel shown in FIG. 3 is about 55 [Cd/m³]. The luminance viewed in frontof the LCD panel in this exemplary embodiment is increased by about 54%than that of the LCD panel shown in FIG. 3. A contrast ratio viewed infront of the LCD panel in this exemplary embodiment is about 150. Acontrast ratio viewed in front of the LCD panel shown in FIG. 3 is about80. The contrast ratio viewed in front of the LCD panel in thisexemplary embodiment is increased by about 180% than that of the LCDpanel shown in FIG. 3. Viewing angles of an upper portion, a lowerportion, a left portion and a right portion of the LCD panel in thisexemplary embodiment are about 44, 42, 36 and 40, respectively. Viewingangles of an upper portion, a lower portion, a left portion and a rightportion of the LCD panel shown in FIG. 3 are about 21, 36, 22 and 38,respectively. Therefore, the viewing angles are increased.

FIG. 10 is an exploded perspective view showing an LCD apparatus inaccordance with another exemplary embodiment of the present invention.Referring to FIG. 10 in which the same reference numerals denote thesame elements in FIG. 3, and thus any further detailed descriptionsconcerning the same elements will be omitted. A reference direction isin substantially parallel with a horizontal direction of an LCD panel ofthe LCD apparatus.

Referring to FIG. 10, the liquid crystal layer is disposed between anarray substrate 100 and a color filter substrate 200. An anisotropy Δnof a reflective index of the liquid crystal layer is about 0.078 ZSM5342with reference to a light having a wavelength of about 589 nm. The‘ZSM5342’ is a unit of the anisotropy Δn of the reflective index. Athickness d1 of the liquid crystal layer is about 3.0 μm. A twist angleof the liquid crystal layer is about 60 degree. A viewing angle of theliquid crystal layer is about 10 degree.

The upper λ/4 retardation film 416 is disposed on the color filtersubstrate 200. A second optical characteristics Δnd2 of the upper λ/4retardation film 416 is about 130 nm to about 150 nm with reference to areference light whose wavelength is about 550 nm. A slow axis of theupper λ/4 retardation film 416 forms at an angle of about 94 degree toabout 114 degree with respect to the reference direction in a clockwisedirection.

The upper λ/2 retardation film 426 is disposed on the upper λ/4retardation film 416. A third optical characteristics Δnd3 of the upperλ/2 retardation film 426 is about 250 nm to about 270 nm with referenceto the reference light whose wavelength is about 550 nm. A slow axis ofthe upper λ/2 retardation film 426 forms at an angle of about 27 degreeto about 47 degree with respect to the reference direction in aclockwise direction.

The upper polarizer 436 is disposed on the upper λ/2 retardation film426. An absorption axis of the upper polarizer 436 forms at an angle ofabout 100 degree to about 120 degree with respect to the referencedirection of the LCD panel in the clockwise direction.

The lower λ/4 retardation film 516 is disposed under the array substrate100. A fourth optical characteristics Δnd4 of the lower λ/4 retardationfilm 516 is about 120 nm to about 140 nm with respect to the referencewavelength. A slow axis of the lower λ/4 retardation film 516 forms atan angle of about 39 degree to about 59 degree with respect to thereference direction in the clockwise direction.

The lower λ/2 retardation film 526 is disposed under the lower λ/4retardation film 516. A fifth optical characteristics Δnd5 of the lowerλ/2 retardation film 526 is about 260 nm to about 280 nm with respect tothe reference wavelength. A slow axis of the lower λ/2 retardation film526 forms at an angle of about 161 degree to about 181 degree withrespect to the reference direction in the clockwise direction.

The lower polarizer 536 is disposed under the lower λ/2 retardation film526. An absorption axis of the lower polarizer 536 forms at an angle ofabout 150 degree to about 170 degree with respect to the referencedirection in the clockwise direction.

In another exemplary embodiment, a slow axis of a lower λ/4 retardationfilm may form at an angle of about 121 degree to about 141 degree withrespect to the reference direction in the clockwise direction. A slowaxis of a lower λ/2 retardation film may form at an angle of about −1degree to about 19 degree with respect to the reference direction in theclockwise direction. An absorption axis of a lower polarizer may form atan angle of about 10 degree to about 30 degree with respect to thereference direction in the clockwise direction.

A light transmittance of the LCD apparatus in this exemplary embodimentis about 0.2658, and a contrast ratio of a transmission mode of the LCDapparatus in this exemplary embodiment is about 4158. The lighttransmittance of the LCD apparatus in this exemplary embodiment isincreased by about 35% than that of the LCD apparatus shown in FIG. 3.The contrast ratio of the transmission mode of the LCD apparatus in thisexemplary embodiment is increased by about 460% than that of the LCDapparatus shown in FIG. 3.

A light reflectivity of the LCD apparatus in this exemplary embodimentis about 8%, and is substantially the same as that of the LCD apparatusshown in FIG. 3. A contrast ratio of the reflection mode of the LCDapparatus in this exemplary embodiment is about 30, and is substantiallythe same as that of the LCD apparatus shown in FIG. 3. A lightreflectivity of an integrating sphere of the LCD apparatus in thisexemplary embodiment is about 5%, and is substantially the same as thatof the LCD apparatus shown in FIG. 3. A contrast ratio of theintegrating sphere of the LCD apparatus in this exemplary embodiment isabout 10, and is substantially the same as that of the LCD apparatusshown in FIG. 3.

A luminance viewed in front of the LCD panel in this exemplaryembodiment is about 77 [Cd/m³]. A luminance viewed in front of the LCDpanel shown in FIG. 3 is about 55 [Cd/m³]. The luminance viewed in frontof the LCD panel in this exemplary embodiment is increased by about 40%than that of the LCD panel shown in FIG. 3. A contrast ratio viewed infront of the LCD panel in this exemplary embodiment is about 190. Acontrast ratio viewed in front of the LCD panel shown in FIG. 3 is about80. The contrast ratio viewed in front of the LCD panel in thisexemplary embodiment is increased by about 230% than that of the LCDpanel shown in FIG. 3. Viewing angles of an upper portion, a lowerportion, a left portion and a right portion of the LCD panel in thisexemplary embodiment are about 44, 42, 36 and 40, respectively. Viewingangles of an upper portion, a lower portion, a left portion and a rightportion of the LCD panel shown in FIG. 3 are about 21, 36, 22 and 38,respectively. Therefore, the viewing angles are increased.

FIGS. 11 and 12 are graphs showing a relationship between a luminanceand a viewing angle when an LCD apparatus in accordance with anotherexemplary embodiment of the present invention displays black color.Radius shown in FIG. 11 represents the viewing angle of an LCD panel ofthe LCD apparatus. A reference direction is in substantially parallelwith a horizontal direction of the LCD panel.

A luminance of a portion of the LCD panel, which corresponds to aviewing angle between about 60 degree and about 80 degree in a directionof about 90 degree in a counter-clockwise direction, is increased. Also,a luminance of a portion of the LCD panel, which corresponds to aviewing angle of about 80 degree in a direction of about 90 degree in aclockwise direction, is increased. A luminance of remaining portion ofthe LCD panel is decreased to display the black color. In particular, aviewing angle viewed in front of the LCD panel is about 0.5 [Cd/m³] sothat an image display quality of the LCD panel is improved.

FIGS. 13 and 14 are graphs showing a relationship between a luminanceand a viewing angle when an LCD apparatus in accordance with anotherexemplary embodiment of the present invention displays white color.

Referring to FIGS. 13 and 14, a luminance of a portion of the LCD panel,which corresponds to a viewing angle of about 0 degree to about 30degree, is increased. A luminance viewed in front of the LCD panel isabout 11 [Cd/m³].

FIGS. 15 and 16 are graphs showing a relationship between a contrastratio and a viewing angle of an LCD apparatus in accordance with anotherexemplary embodiment of the present invention. Radius shown in FIG. 15represents the viewing angle of the LCD panel.

Referring to FIGS. 15 and 16, a contrast ratio of the LCD panelcorresponding to a central portion is higher than that of the LCD panelcorresponding to a peripheral portion to improve the image displayquality of the LCD apparatus.

According to this exemplary embodiment, optical condition of the LCDapparatus is optimized so that the light transmittance and the contrastratio of the LCD apparatus are improved. In addition, the distributionof the viewing angle and the contrast ratio of the LCD apparatus areuniformized so that a color reproductivity and the image display qualityare improved.

Furthermore, the light transmittance of the LCD apparatus is increasedby about 40% to about 50%, and the contrast ratio viewed in front of theLCD panel is increased by about 200%.

FIG. 17 is a cross-sectional view showing an LCD apparatus in accordancewith another exemplary embodiment of the present invention. Referring toFIG. 17 in which the same reference numerals denote the same elements inFIG. 7, and thus any further detailed descriptions concerning the sameelements will be omitted. A reference direction is in substantiallyparallel with a horizontal direction of an LCD panel of the LCDapparatus.

Referring to FIG. 17, the LCD apparatus includes an array substrate 100,a color filter substrate 200, a liquid crystal layer 300, an upperoptical film assembly 400 and a lower optical film assembly 500. Theliquid crystal layer 300 is disposed between the array substrate 100 andthe color filter substrate 200. The upper optical film assembly 400 isdisposed on the color filter substrate 200. The lower optical filmassembly 500 is disposed under the array substrate 100.

The array substrate 100 includes a first transparent plate 105, aswitching element that includes a thin film transistor (TFT), apassivation layer 140 and an organic insulating layer 2144, a pixelelectrode 2150, an insulating interlayer 2152 and a reflecting plate2160. The switching element is formed on the first transparent plate105. The switching element includes a gate electrode 110, a gateinsulating layer 112 that is formed on the first transparent plate 105having the gate electrode 110, a semiconductor layer 114, an ohmiccontact layer 116, a source electrode 120 and a drain electrode 130. Thepassivation layer 140 is formed on the first transparent plate 105having the switching element. The passivation layer 140 includes a firstopening, through which the drain electrode 130 is partially exposed. Theorganic insulating layer 2144 is formed on the passivation layer 140.The organic insulating layer 2144 has a second opening, through whichthe drain electrode 130 is partially exposed. The second opening isdisposed on the first opening. The first and second openings form afirst contact hole 2141. Convex and concave portions may be formed onthe organic insulating layer 2144 to improve a reflective index of areflecting plate 2160. The pixel electrode 2150 is electricallyconnected to the drain electrode 130 through the first contact hole2141. The switching element is formed on a portion of the pixelelectrode 130, which corresponds to the switching element. Thereflecting plate 2160 is formed on the insulating interlayer 2152. Thearray substrate 100 further includes a reflection region and atransmission window 2145. The reflecting plate 2160 is disposed in thereflection region. The reflecting plate 2160 defines the transmissionwindow 2145.

The color filter substrate 200 includes a second transparent plate 2205,a black matrix (not shown), a color filter 2210 and an overcoating layer(not shown). The black matrix is formed on the second transparent plate2205 to define red (R), green (G) and blue (B) pixel regions. The colorfilter 2210 is formed in the red (R), green (G) and the blue (B) pixelregions. The overcoating layer is coated on the second transparent plate2205 having the black matrix and the color filter 2210 to protect theblack matrix and the color filter 2210. A common electrode (not shown)may also be formed on the overcoating layer.

A viewing angle of the liquid crystal layer 300 is about 170 degree toabout 250 degree. A twist angle of the liquid crystal layer 300 is about−10 degree to about +10 degree. The liquid crystal layer 300 is formedbetween the array substrate 100 and the color filter substrate 200. Aliquid crystal of the liquid crystal layer 300 varies an arrangement inresponse to an electric field applied between the pixel electrode 2150of the array substrate 100 and the common electrode of the color filtersubstrate 200, and thus a light transmittance of a natural light thatpasses through the color filter substrate 200 or an artificial lightthat passes through the transmission window 2145 may be changed.

A first thickness d1 of a portion of the liquid crystal layer 300 in thereflection region corresponding to the contact hole 2141, a secondthickness d2 of a portion of the liquid crystal layer 300 in a remainingreflection region, and a third thickness d3 of a portion of the liquidcrystal layer 300 corresponding to the transmission window are differentfrom one another. The first thickness d1 is thicker than the secondthickness d2. The third thickness d3 is thicker than the first thicknessd1.

An anisotropy Δn of a refractive index multiplied by a thickness isequal to an optical characteristics 66 nd. A first opticalcharacteristics Δnd1 corresponds to the portion of the liquid crystallayer 300 in the reflection region corresponding to the contact hole2141. A second optical characteristics Δnd2 corresponds to the portionof the liquid crystal layer 300 in the remaining reflection region. Athird optical characteristics Δnd3 corresponds to the portion of theliquid crystal layer 300 corresponding to the transmission window.

The second thickness d2 may be no more than 1.7 μm. The third thicknessd3 may be no less than 3.3 μm. The first to third thicknesses d1, d2 andd3 may be determined by the liquid crystal of the liquid crystal layer300, the upper optical film assembly 400 and the lower optical filmassembly 500.

The liquid crystal layer 300 has a homogeneous alignment mode. When theliquid crystal layer 300 has the homogeneous alignment mode, a twistangle of the liquid crystal layer 300 is about 0 degree.

The array substrate 100 may include a first alignment layer (not shown)so that the first alignment layer is rubbed in a first rubbing directionthat is in substantially parallel with a horizontal direction. The colorfilter substrate 200 may also include a second alignment layer (notshown) so that the second alignment layer is rubbed in a second rubbingdirection that is in substantially opposite to the first rubbingdirection. Alternatively, the second alignment layer may be rubbed in asecond rubbing direction that is in substantially parallel with thehorizontal direction, and the first alignment layer may be rubbed in afirst rubbing direction that is in substantially opposite to the secondrubbing direction.

In this exemplary embodiment, the array substrate 100 includes the pixelelectrode 150, and the color filter substrate 200 includes the commonelectrode. Alternatively, the LCD apparatus may include a coplanarelectrode (CE) mode, for example, such as an in-plane switching (IPS)mode, a fringe field switching (FFS) mod, etc., so that the color filtersubstrate 200 includes the common electrode.

The upper optical film assembly 400 includes an upper λ/4 retardationfilm 410 disposed on the color filter substrate 200, an upper λ/2retardation film 420 disposed on the upper λ/4 retardation film 420 andan upper polarizer 430 disposed on the upper λ/2 retardation film 420.The lower optical film assembly 500 includes a lower λ/4 retardationfilm 510 disposed under the array substrate 100, a lower λ/2 retardationfilm 520 disposed under the lower λ/4 retardation film 510 and a lowerpolarizer 530 disposed under the lower λ/2 retardation film 520.

FIG. 18 is an exploded perspective view showing an upper optical filmassembly of the LCD apparatus shown in FIG. 17. A reference direction isin substantially parallel with a horizontal direction of an LCD panel ofthe LCD apparatus. A reference wavelength of a light is about 550 nm.

Referring to FIG. 18, the upper λ/4 retardation film 410 is disposed onthe color filter substrate 200. The fourth optical characteristics Δnd4of the upper λ/4 retardation film 410 is about 130 nm to about 150 nm. Aslow axis of the upper λ/4 retardation film 410 forms at an angle ofabout 136 degree to about 156 degree with respect to the referencedirection in a clockwise direction.

The upper λ/2 retardation film 420 is disposed on the upper λ/4retardation film 410. The fifth optical characteristics Δnd5 of theupper λ/2 retardation film 420 is about 250 nm to about 270 nm. A slowaxis of the upper λ/2 retardation film 420 forms at an angle of about 81degree to about 101 degree with respect to the reference direction in aclockwise direction.

The upper polarizer 430 is disposed on the upper λ/2 retardation film420. An absorption axis of the upper polarizer 430 forms at an angle ofabout 67 degree to about 87 degree with respect to the referencedirection of the LCD panel in the clockwise direction.

FIG. 19 is an exploded perspective view showing a lower optical filmassembly of the LCD apparatus shown in FIG. 17.

The lower λ/4 retardation film 510 is disposed under the array substrate100. A sixth optical characteristics Δnd6 of the lower λ/4 retardationfilm 510 is about 120 nm to about 140 nm with respect to the referencewavelength. A slow axis of the lower λ/4 retardation film 510 forms atan angle of about −1 degree to about +19 degree with respect to thereference direction in the clockwise direction.

The lower λ/2 retardation film 520 is disposed under the lower λ/4retardation film 516. A seventh optical characteristics Δnd7 of thelower λ/2 retardation film 520 is about 260 nm to about 280 nm withrespect to the reference wavelength. A slow axis of the lower λ/2retardation film 520 forms at an angle of about 113 degree to about 133degree with respect to the reference direction in the clockwisedirection.

The lower polarizer 530 is disposed under the lower λ/2 retardation film520. An absorption axis of the lower polarizer 530 forms at an angle ofabout 8 degree to about 28 degree with respect to the referencedirection in the clockwise direction.

In another exemplary embodiment, a slow axis of a lower λ/4 retardationfilm may form at an angle of about 161 degree to about 181 degree withrespect to the reference direction in the clockwise direction. A slowaxis of a lower λ/2 retardation film may form at an angle of about 47degree to about 67 degree with respect to the reference direction in theclockwise direction. An absorption axis of a lower polarizer may form atan angle of about 152 degree to about 172 degree with respect to thereference direction in the clockwise direction.

Alternatively, the second and third thicknesses d2 and d3 may besubstantially equal to each other.

The LCD apparatus may also include a reflective type LCD apparatushaving a switching element, a pixel electrode that is electricallyconnected to a drain electrode of the switching element and a reflectingplate that is formed on the pixel electrode to reflect the naturallight.

The LCD apparatus may also include a bottom ITO type. A pixel electrodeof the bottom ITO typed LCD apparatus is formed under the organicinsulating layer.

FIG. 20 is a cross-sectional view showing a reflection mode of the LCDapparatus shown in FIG. 17. FIG. 21 is a cross-sectional view showing atransmission mode of the LCD apparatus shown in FIG. 17. The LCDapparatus includes the liquid crystal layer 300 having a normally whitemode. When an electric field is not applied to the liquid crystal layer300 having the normally white mode, the LCD apparatus displays whitecolor.

Referring to FIG. 20, when the electric field is not applied to theliquid crystal layer 300 in the reflection mode, the liquid crystal ofthe liquid crystal layer 300 is horizontally aligned. The natural lightthat is provided from an exterior to the liquid crystal layer 300 passesthrough the upper polarizer 420 so that the natural light is convertedinto a linearly polarized light. The linearly polarized light passesthrough the upper λ/4 retardation film 410 so that the linearlypolarized light is converted into a left circularly polarized light.Alternatively, the linearly polarized light passes through the upper λ/4retardation film 410 so that the linearly polarized light may beconverted into a right circularly polarized light.

The left circularly polarized light passes through the liquid crystallayer 300 so that a phase of the left circularly polarized light isdelayed by λ/4 to form a linearly polarized light. The opticalcharacteristics of the liquid crystal layer 300 corresponding to thereflection mode are represented by the reference numeral Δnd2. Thelinearly polarized light that passes through the liquid crystal layer300 is reflected from the reflecting plate 160. The reflecting plate mayinclude an aluminum-neodymium (Al—Nd) alloy. The reflected light passesthrough the liquid crystal layer 300 so that a phase of the reflectedlight is delayed by λ/4 to form a left circularly polarized light.

The left circularly polarized light that is formed from the reflectedlight passes through the upper λ/4 retardation film 410 so that the leftcircularly polarized light is converted into a linearly polarized light.The linearly polarized light passes through the upper polarizer 420 sothat the white color is displayed.

When the electric field is applied to the liquid crystal layer 300 inthe reflection mode, the liquid crystal of the liquid crystal layer 300is vertically aligned. The natural light that is provided from theexterior to the LCD apparatus passes through the upper polarizer 420 sothat the natural light is converted into a linearly polarized light. Thelinearly polarized light passes through the upper λ/4 retardation film410 so that the linearly polarized light is converted into a leftcircularly polarized light.

The left circularly polarized light passes through the liquid crystallayer 300, and the left circularly polarized light remains unchanged.The left circularly polarized light that passes through the liquidcrystal layer 300 is reflected from the reflecting plate 160 so that theleft circularly polarized light is converted into a right circularlypolarized light. The right circularly polarized light passes through theliquid crystal layer 300, and the right circularly polarized lightremains unchanged. The right circularly polarized light passes throughthe upper λ/4 retardation film 410 so that the right circularlypolarized light is converted into a linearly polarized light. Thelinearly polarized light is blocked by the upper polarizer to displayblack color.

Referring to FIG. 21, when the electric field is not applied to theliquid crystal layer 300 in the transmission mode, the liquid crystal ofthe liquid crystal layer 300 is horizontally aligned. The artificiallight generated from a backlight assembly passes through the lowerpolarizer 520 so that the artificial light is converted into a linearlypolarized light. The linearly polarized light passes through the lowerλ/4 retardation film 510 so that the linearly polarized light isconverted into a right circularly polarized light. The right circularlypolarized light passes through the pixel electrode that is transparentso that the right circularly polarized light remains unchanged. Thesecond optical characteristics Δnd2 of the liquid crystal layer 300corresponding to the reflection region is about a half of the thirdoptical characteristics Δnd3 of the liquid crystal layer 300corresponding to the transmission window 2145.

The right circularly polarized light that passes through the liquidcrystal layer 300 so that a phase of the right circularly polarizedlight is delayed by λ/2 to form a right circularly polarized light. Theright circularly polarized light passes through the upper λ/4retardation film 410 so that the right circularly polarized light isconverted into a linearly polarized light. The linearly polarized lightpasses through the upper polarizer 420 to display the white color.

When the electric field is applied to the liquid crystal layer 300 inthe transmission mode, the liquid crystal of the liquid crystal layer300 is vertically aligned. The artificial light generated from thebacklight assembly passes through the lower polarizer 520 so that theartificial light is converted into a linearly polarized light. Thelinearly polarized light passes through the lower λ/4 retardation film510 so that the linearly polarized light is converted into a rightcircularly polarized light. The right circularly polarized light passesthrough the pixel electrode 150 so that the right circularly polarizedlight remains unchanged.

The right circularly polarized light that passes through the pixelelectrode 150 passes through the liquid crystal layer 300 so that theright circularly polarized light remains unchanged.

The right circularly polarized light that passes through the liquidcrystal layer 300 passes through the upper λ/4 retardation film 410 sothat the right circularly polarized light is converted into a linearlypolarized light. The linearly polarized light is blocked by the upperpolarizer 420 to display the black color.

FIGS. 22 and 23 are graphs showing a relationship between a luminanceand a viewing angle when an LCD apparatus in accordance with anotherexemplary embodiment of the present invention displays black color.Radius shown in FIG. 22 represents the viewing angle of an LCD panel ofthe LCD apparatus. A reference direction is in substantially parallelwith a horizontal direction of the LCD panel.

Referring to FIGS. 22 and 23, a luminance of a portion of the LCD panel,which corresponds to a viewing angle between about 60 degree and about80 degree in a direction at an angle of about 90 degree to about 120degree in a counter-clockwise direction, is increased. Also, a luminanceof a portion of the LCD panel, which corresponds to a viewing angle ofabout 40 degree to about 80 degree in a direction in substantiallyparallel with the reference direction, is increased. In addition, aluminance of a portion of the LCD panel, which corresponds to a viewingangle of about 80 degree in a direction at an angle of about 90 degreeto about 120 degree in a clockwise direction, is increased. A luminanceof remaining portion of the LCD panel is decreased to display the blackcolor. In particular, a viewing angle viewed in front of the LCD panelis about 0.5 [Cd/m³] so that an image display quality of the LCD panelis improved.

FIGS. 24 and 25 are graphs showing a relationship between a luminanceand a viewing angle when an LCD apparatus in accordance with anotherexemplary embodiment of the present invention displays white color.Radius shown in FIG. 24 represents the viewing angle of an LCD panel ofthe LCD apparatus.

Referring to FIGS. 24 and 25, a luminance of a portion of the LCD panel,which corresponds to a viewing angle of about 0 degree to about 30degree, is increased. A luminance viewed in front of the LCD panel isabout 11 [Cd/m³].

FIGS. 26 and 27 are graphs showing a relationship between a contrastratio and a viewing angle of an LCD apparatus in accordance with anotherexemplary embodiment of the present invention. Radius shown in FIG. 26represents the viewing angle of the LCD panel.

Referring to FIGS. 26 and 27, a contrast ratio of the LCD panelcorresponding to a central portion is higher than that of the LCD panelcorresponding to a peripheral portion to improve the image displayquality of the LCD apparatus.

Hereinafter, the LCD apparatus having the optical film assembly shown inFIGS. 18 and 19 is compared with the LCD apparatus having the opticalfilm assembly shown in FIG. 8.

The optical film assembly shown in FIG. 8 includes the upper λ/4retardation film 412, the upper λ/2 retardation film 422, the upperpolarizer 432, the lower λ/4 retardation film 512, the lower λ/2retardation film 522 and the lower polarizer 532. The second opticalcharacteristics Δnd2 of the upper λ/4 retardation film 412 may be about140 nm, and the slow axis of the upper λ/4 retardation film 412 may format an angle of about 44 degree with respect to the reference directionin the clockwise direction. The third optical characteristics Δnd3 ofthe upper λ/2 retardation film 422 may be about 260 nm, and the slowaxis of the upper λ/2 retardation film 422 may form at an angle of about166 degree with respect to the reference direction in the clockwisedirection. The absorption axis of the upper polarizer 432 may form at anangle of about 150 degree with respect to the reference direction of theLCD panel in the clockwise direction. The fourth optical characteristicsΔnd4 of the lower λ/4 retardation film 512 may be about 145 nm withrespect to the reference wavelength, and the slow axis of the lower λ/4retardation film 512 may form at an angle of about 46 degree withrespect to the reference direction in the clockwise direction. The fifthoptical characteristics Δnd5 of the lower λ/2 retardation film 522 maybe about 270 nm, and the slow axis of the lower λ/2 retardation film 522may form at an angle of about 105 degree with respect to the referencedirection in the clockwise direction. The absorption axis of the lowerpolarizer 532 may form at an angle of about 120 degree with respect tothe reference direction in the clockwise direction.

The optical film assembly shown in FIGS. 18 and 19 includes the upperλ/4 retardation film 410, the upper λ/2 retardation film 420, the upperpolarizer 430, the lower λ/4 retardation film 510, the lower λ/2retardation film 520 and the lower polarizer 530. The fourth opticalcharacteristics Δnd4 of the upper λ/4 retardation film 410 may be about140 nm, and the slow axis of the upper λ/4 retardation film 410 may format an angle of about 146 degree with respect to the reference directionin the clockwise direction. The fifth optical characteristics Δnd5 ofthe upper λ/2 retardation film 420 may be about 260 nm, and the slowaxis of the upper λ/2 retardation film 420 may form at an angle of about91 degree with respect to the reference direction in the clockwisedirection. The absorption axis of the upper polarizer 430 may form at anangle of about 77 degree with respect to the reference direction of theLCD panel in the clockwise direction. The sixth optical characteristicsΔnd6 of the lower λ/4 retardation film 510 may be about 130 nm withrespect to the reference wavelength, and the slow axis of the lower λ/4retardation film 510 may form at an angle of about 9 degree with respectto the reference direction in the clockwise direction. The seventhoptical characteristics Δnd7 of the lower λ/2 retardation film 520 maybe about 270 nm, and the slow axis of the lower λ/2 retardation film 520may form at an angle of about 123 degree with respect to the referencedirection in the clockwise direction. The absorption axis of the lowerpolarizer 530 may form at an angle of about 18 degree with respect tothe reference direction in the clockwise direction.

A light reflectivity of the LCD apparatus having the optical filmassembly shown in FIG. 8 is about 8%, and is substantially the same asthat of the LCD apparatus having the optical film assembly shown inFIGS. 18 and 19. A contrast ratio of the reflection mode of the LCDapparatus having the optical film assembly shown in FIG. 8 is about 30,and is substantially the same as that of the LCD apparatus having theoptical film assembly shown in FIGS. 18 and 19. A light reflectivity ofan integrating sphere of the LCD apparatus having the optical filmassembly shown in FIG. 8 is about 5%, and is substantially the same asthat of the LCD apparatus having the optical film assembly shown inFIGS. 18 and 19. A contrast ratio of the integrating sphere of the LCDapparatus having the optical film assembly shown in FIG. 8 is about 10,and is substantially the same as that of the LCD apparatus having theoptical film assembly shown in FIGS. 18 and 19.

A luminance viewed in front of the LCD panel having the optical filmassembly shown in FIG. 8 is about 70 [Cd/m³]. A luminance viewed infront of the LCD panel having the optical film assembly shown in FIGS.18 and 19 is about 180 [Cd/m³]. The luminance viewed in front of the LCDpanel having the optical film assembly shown in FIGS. 18 and 19 isincreased by about 260% than that of the LCD panel having the opticalfilm assembly shown in FIG. 8. A contrast ratio viewed in front of theLCD panel having the optical film assembly shown in FIG. 8 is about 110.A contrast ratio viewed in front of the LCD panel having the opticalfilm assembly shown in FIGS. 18 and 19 is about 250. The contrast ratioviewed in front of the LCD panel having the optical film assembly shownin FIGS. 18 and 19 is increased by about 230% than that of the LCD panelhaving the optical film assembly shown in FIG. 8. Viewing angles of anupper portion, a lower portion, a left portion and a right portion ofthe LCD panel having the optical film assembly shown in FIG. 8 are about28, 28, 52 and 22, respectively. Viewing angles of an upper portion, alower portion, a left portion and a right portion of the LCD panel shownin FIGS. 18 and 19 are about 50, 50, 50 and 48, respectively. Therefore,the viewing angles are increased.

According to the present invention, the optical conditions of the upperand lower optical film assembly are optimized so that the lighttransmittance, the contrast ratio and the viewing angle of the LCDapparatus are improved.

The LCD apparatus includes a reflective type LCD apparatus, atransmissive type LCD apparatus or a transmissive-reflective LCDapparatus. In the transmissive-reflective LCD apparatus, the thicknessof the liquid crystal layer corresponding to the reflection region isdifferent from that of the liquid crystal layer corresponding to thetransmission window. Alternatively, the thickness of the liquid crystallayer corresponding to the reflection region may be substantially thesame as that of the liquid crystal layer corresponding to thetransmission window.

This invention has been described with reference to the exemplaryembodiments. It is evident, however, that many alternative modificationsand variations will be apparent to those having skill in the art inlight of the foregoing description. Accordingly, the present inventionembraces all such alternative modifications and variations as fallwithin the spirit and scope of the appended claims.

1. An optical film assembly for a liquid crystal display panel includinga liquid crystal layer having a twist angle of about −10 degree to about+10 degree, the optical film assembly comprising: an upper polarizerdisposed over an upper substrate of the liquid crystal display panel,the upper polarizer including an absorption axis forming at an angle ofabout 37 degree to about 57 degree in a clockwise direction with respectto a major axis of a liquid crystal of the liquid crystal layer, and theliquid crystal being disposed adjacent to the upper substrate; an upperλ/2 retardation film disposed between the upper substrate and the upperpolarizer, the upper λ/2 retardation film including a first opticalcharacteristics Δnd1 of about 250 nm to about 270 nm, a slow axis of theupper λ/2 retardation film forming at an angle of about 156 degree toabout 176 degree in the clockwise direction with respect to theabsorption axis; and an upper λ/4 retardation film disposed between theupper substrate and the upper λ/2 retardation film, the upper λ/4retardation film including a second optical characteristics Δnd2 ofabout 130 nm to about 150 nm, a slow axis of the upper λ/4 retardationfilm forming at an angle of about 101 degree to about 121 degree in theclockwise direction with respect to the absorption axis, wherein ‘Δn’,‘d1’ and ‘d2’ denote an anisotropy of a refractive index, a thickness ofthe upper λ/2 retardation film and a thickness of the upper λ/4retardation film, respectively.
 2. An optical film assembly for a liquidcrystal display panel including a liquid crystal layer having a twistangle of about −10 degree to about +10 degree, the optical film assemblycomprising: a lower polarizer disposed under a lower substrate of theliquid crystal display panel, the lower polarizer including anabsorption axis forming at an angle of about 38 degree to about 58degree in a clockwise direction with respect to a major axis of a liquidcrystal of the liquid crystal layer, and the liquid crystal beingdisposed adjacent to the lower substrate; a lower λ/2 retardation filmdisposed between the lower substrate and the lower polarizer, the lowerλ/2 retardation film including a first optical characteristics Δnd1 ofabout 260 nm to about 280 nm, a slow axis of the lower λ/2 retardationfilm forming at an angle of about 65 degree to about 85 degree in theclockwise direction with respect to the absorption axis; and a lower λ/4retardation film disposed between the lower substrate and the lower λ/2retardation film, the lower λ/4 retardation film including a secondoptical characteristics Δnd2 of about 120 nm to about 140 nm, a slowaxis of the lower λ/4 retardation film forming at an angle of about −1degree to about 19 degree in the clockwise direction with respect to theabsorption axis, wherein ‘Δn’, ‘d1’ and ‘d2’ denote an anisotropy of arefractive index, a thickness of the lower λ/2 retardation film and athickness of the lower λ/4 retardation film, respectively.
 3. A liquidcrystal display apparatus comprising: a liquid crystal display panelincluding an upper substrate, a lower substrate corresponding to theupper substrate and a liquid crystal layer disposed between the upperand lower substrates to have a twist angle of about −10 degree to about+10 degree; an upper polarizer disposed over the upper substrate, theupper polarizer including an absorption axis forming at an angle ofabout 37 degree to about 57 degree in a clockwise direction with respectto a major axis of a liquid crystal of the liquid crystal layer, and theliquid crystal being disposed adjacent to the upper substrate; an upperλ/2 retardation film disposed between the upper substrate and the upperpolarizer, the upper λ/2 retardation film including a first opticalcharacteristics Δnd1 of about 250 nm to about 270 nm, a slow axis of theupper λ/2 retardation film forming at an angle of about 156 degree toabout 176 degree in the clockwise direction with respect to theabsorption axis; and an upper λ/4 retardation film disposed between theupper substrate and the upper λ/2 retardation film, the upper λ/4retardation film including a second optical characteristics Δnd2 ofabout 130 nm to about 150 nm, a slow axis of the upper λ/4 retardationfilm forming at an angle of about 101 degree to about 121 degree in theclockwise direction with respect to the absorption axis, wherein ‘Δn’,‘d1’ and ‘d2’ denote an anisotropy of a refractive index, a thickness ofthe upper λ/2 retardation film and a thickness of the upper λ/4retardation film, respectively.
 4. The liquid crystal display apparatusof claim 3, wherein the liquid crystal layer comprises a homogeneousalignment mode.
 5. The liquid crystal display apparatus of claim 3,wherein the lower substrate comprises a switching element, a pixelelectrode electrically connected to a drain electrode of the switchingelement and a reflecting plate formed on the pixel electrode to reflectan artificial light.
 6. The liquid crystal display apparatus of claim 3,wherein the lower substrate comprises a switching element, a pixelelectrode electrically connected to a drain electrode of the switchingelement, a reflection region where a natural light is reflected from anda transmission window where an artificial light passes through.
 7. Theliquid crystal display apparatus of claim 6, wherein the liquid crystallayer comprises a first thickness corresponding to the reflection regionand a second thickness corresponding to the transmission window, and thefirst thickness is different from the second thickness.
 8. A liquidcrystal display apparatus comprising: a liquid crystal display panelincluding an upper substrate, a lower substrate and a liquid crystallayer disposed between the upper and lower substrates to have a twistangle of about −10 degree to about +10 degree; a lower polarizerdisposed under the lower substrate, the lower polarizer including anabsorption axis forming at an angle of about 38 degree to about 58degree in a clockwise direction with respect to a major axis of a liquidcrystal of the liquid crystal layer, and the liquid crystal beingdisposed adjacent to the lower substrate; a lower λ/2 retardation filmdisposed between the lower substrate and the lower polarizer, the lowerλ/2 retardation film including a first optical characteristics Δnd1 ofabout 260 nm to about 280 nm, a slow axis of the lower λ/2 retardationfilm forming at an angle of about 65 degree to about 85 degree in theclockwise direction with respect to the absorption axis; and a lower λ/4retardation film disposed between the lower substrate and the lower λ/2retardation film, the lower λ/4 retardation film including a secondoptical characteristics Δnd2 of about 120 nm to about 140 nm, a slowaxis of the lower λ/4 retardation film forming at an angle of about −1degree to about 19 degree in the clockwise direction with respect to theabsorption axis, wherein ‘Δn’, ‘d1’ and ‘d2’ denote an anisotropy of arefractive index, a thickness of the lower λ/2 retardation film and athickness of the lower λ/4 retardation film, respectively.
 9. The liquidcrystal display apparatus of claim 8, wherein the liquid crystal layercomprises a homogeneous alignment mode.
 10. The liquid crystal displayapparatus of claim 8, wherein the lower substrate comprises a switchingelement, a pixel electrode electrically connected to a drain electrodeof the switching element and a reflecting plate formed on the pixelelectrode to reflect an artificial light.
 11. The liquid crystal displayapparatus of claim 8, wherein the lower substrate comprises a switchingelement, a pixel electrode electrically connected to a drain electrodeof the switching element, a reflection region where a natural light isreflected from and a transmission window where an artificial lightpasses through.
 12. The liquid crystal display apparatus of claim 11,wherein the liquid crystal layer comprises a first thicknesscorresponding to the reflection region and a second thicknesscorresponding to the transmission window, and the first thickness isdifferent from the second thickness.